American Air Mail Society Founded 1923

Safe Landing


Editor’s Note: This glossary first appeared in the February 1995 Airpost Journal, with an invitation to readers to suggest additions, corrections, or other amendments. This is the final result of this effort.

     The spectrum of aerophilatelic covers is wide. This glossary is intended to provide the philatelist with general defini­tions of the types of covers and an understanding of the differences.

     The first separation to be made is quite basic:

     Carried on an aerial flight and bearing evidence of being flown. (This definition is taken directly from the FIP definition of aerophilately.)

     Covers flown with postal authorization are official, i.e., officially flown; if flown without postal authorization, a cover is unofficial, i.e., private. Distinguish official(ly) flown from flown official, the latter being any mail of an official governmental authorized agency (indicated by special official governmental agency markings or bearing official overprinted/issued stamps, sent by airmail.)

     Not carried on any aerial flight, but directly related to an aero or astro event or anniversary,
     Cover from a planned or projected flight which was not made,
     Cover directed to be flown but not flown due to no flight planned or made, unavailable service, weather factors, or other reason.
Although not flown, these are usually grouped with the flown covers, together with explanation as to why not flown.

     The flown covers are the foundation of aerophilately. There are many different types and classes of flown covers.

Flown Covers

Air Express
     Flown by the Air Express service operated by the Railway Express Agency (United States or Great Britain).

     Photographed airmail letter. Microfilm of original letter was flown, then enlarged and printed on a special form at its destination. Process was used during the Siege of Paris (1870-71) and again during World Wars I and II (sometimes referred to in the U.S. as “V-Mail”).

Airlift Flight
     Flight made to carry mail to otherwise inaccessible location due to blockade or enemy occupation of usual access routes.

     Flown by airship, either:
a) A lighter-than-air (LTA) craft characterized by a rigid, covered framework, the interior of which holds containment cells for the lifting gas, e.g., a Zeppelin,
b) A non-rigid LTA craft, the form of which holds the lifting gas, e.g., a blimp.

Airway Letter
     Flown by a private air letter service operated by an airline.

Ambulance Cover
     Envelope used to carry and deliver a severely damaged piece of mail, e.g., a crash cover.

Attempted Flight
     Flight which failed to achieve its goal, e.g., altitude, distance or destination.

Balloon Flight
     Flight made by a balloon.
     The most famous balloon flight mails are those flown out of Paris during the German siege of 1870-1871:

§ Balloon Monte: Manned balloon. The covers themselves are also referred to by this name. (French spelling is “Ballon”)
§ Balloon Non Monte: Unmanned balloon.
     In Europe, mail-carrying balloon flights are often made on behalf of charitable organizations, e.g., Pro Juventute in Switzerland, Austria and Germany.
     Souvenir mail is also frequently carried by balloons competing in balloon flight competitions.

     See Contract Flight.

Cancelled Flight
     Planned flight which was not made due to adverse weather, damaged aircraft, no aircraft available, or other reason.
Note: A cancelled flight cover would be an example of a non-flown cover, but important enough to be grouped with flown covers if either the proposed flight or the reason for cancellation was of significant importance.

Catapult Flight
     Flight made by an aircraft launched by a catapult system, usually from on board a ship. The “ship-to-shore” catapult airmail is sometimes referred to by that term.
     Most frequently refers to the catapult flights in the North Atlantic in the period 1928-1935 (French and German), but other major routes also used this method, most notably the Deutsche Lufthansa South Atlantic airmail service.

Combination Cover
     Cover transported by air and one (or more) other (non-air) primary means in transit to the original destination.
Example: Flight plus surface means (sea or rail).
Indication, preferably by postal markings, of both the flight route and the surface transport are mandatory.
Note: All covers have obviously had some surface transport. The combination cover is one with primary transport by differing means over major parts of the total route.

Combination Flight Cover
     Cover flown by two different airmail means in transit to the original destination.
May be either . .
§ Two flights in sequence to expedite delivery
§ Two separated flights

Commemorative Flight
     Flight retracing all or part of prior, historically important, flight or commemorating an important aviation event.

Connecting (or Connection) Flight
     Flight dedicated to making connection for mail/passengers with another flight or another means of transport, usually just prior to departure or at a specified mid-route point. See also: Feeder Flight, Supplementary Flight.

Contract Air Mail Flight
     Flight made on a United States air mail route flown by a carrier under contract with the United States Post Office (and later the United States Postal Service) in either the period February 15, 1926 – February 19, 1934 or May 8, 1934 – November 30, 1978.

Courtesy Acceptance
     Foreign origin mail accepted for airmail service absent an international postal treaty or agreement to accept it.

Courtesy Preflown (also: “Courtesy” or “Favor”)
     Flown without postal authorization as a courtesy prior to posting at a post office.

     Incomplete flight due to aircraft accident resulting in damage to or destruction of the aircraft, with mails (if not lost) forwarded by other aircraft or other means (sometimes referred to as “recovered” or “salvaged” mail).
     Covers with postal markings indicating the crash are preferred when available. More than one type of marking was used on the mails of some crashes.
     Mail damaged in the crash is an exception to the usual standards of condition. Severely damaged crash mail may have an accompanying “ambulance cover.”

     Deferred (late) departure / arrival vs. scheduled time. Lateness caused by deferred departure or prolonged planned flight stopover unrelated to in-flight problem.

Demonstration Flight
     Flight made to show feasibility of service or the reliability of the aircraft used.

Direct Flight
     Flight between two points without intermediate landing. Non-stop flight

     All steerable lighter-than-air (LTA) craft. See Airship.

Diverted Flight
     Flight directed to an alternate landing point, i.e., diverted from the planned route, usually due to adverse weather conditions at scheduled landing site, but may be due to other reason (e.g., armed activity).

Double Flown
     Cover flown once, then re-addressed and flown again. See also: Round Trip Cover.

Dropped Mail
     Mail dropped from the air for forwarding. Usually done because there was no airport or landing place for the aircraft, or to hasten mail delivery when landing procedures were prolonged or delayed.
     Drops were made by “free fall”, mail bags lowered by rope, or by parachute (see parachute).
Note: Propaganda leaflets dropped during wartime are not generally considered as mail because the leaflets were not mail per se as they were not postal and were unaddressed.

Emergency Flight
     Flight undertaken in response to an emergency.
     AAMS Catalogue Definition: Special arrangements made for the conveyance of mail during periods of emergency, such as floods, severe storms, breakdown of rail transportation, strikes, and other conditions requiring the abnormal dispatch of mail.
Note: Many of the so-called “emergency” flights within Alaska were not emergencies at all, but simply the use of an airplane to forward mails because either no other means was then available or the airplane offered the most expeditious delivery.

Experimental Flight
     See Survey Flight. Cf. Trial Flight.

Express Air Mail
     Priority air mail service at a higher rate than regular airmail.

Exploratory Flight
     Flight made for primary purpose of exploring an area or territory.

     See Foreign Air Mail.

Feeder Flight
     See Connecting Flight. Feeder flight usually refers to an airmail connection flight at a specified mid-route point (rather than a connection flight made immediately prior to initial departure). See also Supplementary Flight.

First Acceptance
     First airmail dispatch from a specified origin on an existing route or service.

First Flight (also: “Inaugural Flight”)
     Initial flight (airline, route, or aircraft) with official airmail.
        Note: Distinguish from “first flight” without airmail, e.g., see “maiden flight”.
     First flight by carrier on new or extended scheduled route, or with new aircraft type.
Note: Aircraft could be a new type or simply an additional airplane on the route for expanded service. Example: Inaugural service of NC-14714 Hawaii Clipper and NC-14715 Philippine Clipper, listed in AAMC 5th Edition, Volume 1, page 421.

Flight Leg
     A point-to-point dispatch or segment of a longer route.

Foreign Air Mail (FAM)
     Foreign (international) contract air mail route flown by a United States airline under contract with the United States Post Office from U.S. point(s) to a foreign country and vice versa.

Glider Flight
     Flight by glider or sailplane (unpowered aircraft).

Inaugural Flight
     See First Flight.

Interrupted Flight
     Non-continuous flight. In-flight problem resulting in unplanned landing (usually due to weather conditions or aircraft mechanical problem). Flight continued later by the same aircraft or, to expedite mail, another aircraft.
Note: The terms “crash” and “interrupted flight” were some­times used interchangeably, e.g., in the American Air Mail Cata­logue, which then defines these covers as from: “an important interruption or mishap on a scheduled air mail route, capable of identification by cachet, postmark, physical damage, routing or official memoranda” but not including minor accidents or forced landings because usually no appreciable delay or damage to mail results.
The definitions in this Glossary clarify these terms. The old definition cited in this Note should not be used.

Last Flight
     Final flight on a specific route or by a specific carrier.

Lighter-Than-Air (LTA)
     Encompassing all air travel means of this type, including both balloons and dirigibles.

Maiden Flight
     Flown with a specific aircraft, usually a new type of mili­tary, commercial or experimental aircraft, and posted at the end of the flight. The flight is not a flight with airmail; the covers are unofficial, usually prepared by aircraft company per­sonnel for placement on the first flight of a new aircraft type. NOTE: Sometimes referred to as “Aircraft Covers.”

Military Flight
     Flight authorized and conducted/flown by military personnel and aircraft.

Multiple Flight
     Cover flown by two or more flights of the same basic means, each with postal directions, markings or cachets to show the different flights.

     Flight between two points without intermediate landing. Direct flight.

     Cover dropped by parachute. May be souvenirs of a special event, but occasionally are official mail dropped where an airplane cannot land.
     Zeppelin mails were frequently dropped by parachute, either prior to landing to expedite mail transmission, or over an airfield to avoid the delay and/or expense of landing.
     See also: Dropped Mail.

Pickup Airmail
     Airmail picked up by a passing aircraft in flight without landing.

Pigeon Mail
     Mail carried by pigeon, either on microfilm or a small, very light-weight letter sheet (“pigeongram” or “flimsy”) carried in a pellicule attached to the leg of the bird for flight.

Pioneer Flight
     Flight from the period beginning with the initial experimental flights and ending with the beginning of regular air services. Pioneer flights carried small amounts of mail authorized by either national or local postal authorities.
     For the United States, the “pioneer period” is 1910 – 1918. In general, the term “pioneer” airmail refers to the period from the beginning of aviation to the early 1920s at the latest.

Projected Flight
     Planned flight which did not take place. See also: Cancelled Flight.
     A “projected flight” is basically an early cancellation, the cancellation of a plan rather than the cancellation of an actual flight.

Proving Flight
     Proving flight is a term used by U.S. airlines. Primary intent is to familiarize crew members with new aircraft or route. Sometimes referred to “familiarization” flights. These flights in many instances carried mail and non-paying passengers.

Rate Change Cover
     Flown cover posted on the first day of a new airmail rate.

Record Flight
     Flight that sets a new record for speed, distance, altitude or endurance.

Rocket Flight
     Flight by any rocket.
     Early rocket pioneers sometimes placed souvenir cards or covers in their rockets. This is referred to as “rocket mail”.
     Astrophilatelists mark significant rocket flights by covers posted at the launch site (or its nearest post office) on the launch date. These are non-flown covers, but keys in astrophi­lately.

Round Trip Cover
     Cover flown both ways on a round trip without readdressing.

     Unofficial flown cover, usually carried by pilot or crew member, or for promotional or commercial purpose. Many of the early Concorde SST covers were carried by passengers.

Souvenir (Historical)
     Flown souvenirs from important events which contributed to the development of aviation. Usually not official. Most carried on pathfinder flights (predating the opening of official airmail routes).

Special Flight
     Flight made for specific purpose (non-emergency).

Supplementary Flight
     Flight service intended primarily to advance late mails with another transport service. See Feeder Flight.

Star Route Services
     U.S. contracts made for the transportation of mail between post offices not served directly by normal rail, water or air transportation, and which are dependent on an office so served for mail receipt and dispatch.

Survey Flight (also: “Experimental Flight”)
     Flight made to assess the viability of a proposed or projected commercial flight route.
     Flight made prior to introduction of regular service on a new route (for crew familiarization).
     Cf. Trial Flight.

Test Cover
     Cover mailed to evaluate efficiency of airmail delivery system. Example: Test cover sent via new airmail service by competing airline of another nation during the development period.

Through Flight
     Flight with intermediate stop(s) enroute to destination without change of aircraft.

Treaty Acceptance
     Foreign origin mail accepted for airmail service pursuant to an international treaty or agreement providing for rates and compensation.

Trial Flight (also: “Test Flight”)
     Flight made to evaluate aircraft or system.
Cf. Proving Flight.

     Cover flown trans-ocean twice en route to its original destination.

U.S. Government Flight
     Air mail services conducted under federal authority by the Signal Corps of the U.S. Army, the Post Office Department, or other federal bureau in pioneering subsequent commercial airmail route within the United States. Usually used for the U.S. airmail flights of the period May 15, 1918 – August 31, 1927.

     A German dirigible airship built by Count Ferdinand von Zeppelin; his company, Luftschiffbau Zeppelin; or its related (e.g., Goodyear Zeppelin) or successor companies (e.g., Deutsche Zeppelin Reederei).

Non-Flown Covers

     Not carried on any aerial flight, but related to an aero or astro event or anniversary.
          Aero Event: Airship visit, air exhibition, new aircraft introduction, visit by major aviation personality, etc.
          Aerophilatelic exhibition
          Astro Event: Launch, mission performed in space, landing.
          Airport dedication

     Note: Presence of airmail postage stamps is not conclusive evidence of being flown. Attention and consideration must be given to the dispatch point and destination, availability of airmail services, alternative means which may have been used, transit time (if evidenced), airmail postal rates, and other evidence of the circumstances, conditions and intent.


I wish to thank the following aerophilatelists for their contributions in the development of this glossary:

Murray Heifetz
Alexander S. Newall
Philip McCarty
Frans J. van Beveren
Kendall Sanford
Robert Wilcsek
Chris Hargreaves
Dave Savadge
Mike Shand
Dr. Richard H. Saundry
John Duggan
Jim Brown
Robert Hunter
Carl Freund
Jonathan L. Johnson, Jr.

Classes of Combination Covers – Frans van Beveren

     Frans van Beveren, an eminent aerophilatelist of the Netherlands, introduced his concept of “combi-cover” in 1990 as:
          Combi-cover: Cover which clearly shows dual means of transport.
Six different classes of combi-covers were identified.
     In 1994, van Beveren revised the base definition:
Combi-cover: Airmail cover which has received other official postal markings indicating dual means of transport, excluding first flight cachets.

Fourteen different classes of combi-covers are listed:

1. Airmail service for entire (or most of the) route not yet available or no corresponding connection flight, making surface transport faster. (Original Class A)
           a. Complete handstamped cachets or printed labels showing the flown stage.
           b. Cachets with manuscript insertion by postal officials for destination.
           c. Other postal strikes showing air transport on part of the mail route.
2. Obliterated airmail labels or other aero-indications marking the end of the flown route. (Original Class B)
3. Missed connection between postal airplane and surface transport or connecting flight.
4. Mail showing dual transport by airmail and surface means (e.g., sea or rail) by post office cachets, cancellations or other markings. (Original Class E)
5. Postal markings and/or added postage due to insufficient postage paid for entire airmail service (fault of sender). (Original Class D).
6. Airmail service available, but less expensive alternative service providing satisfactory delivery time used. (Original Class C).
7. Mail flown over full route with special postal markings showing connecting flight. Examples: Feeder flight, airfield route cancels, “via” route indications, and airline cachets or labels.
8. Propaganda for airmail. Examples: Cachets on flown mail.
9. Mail with O.A.T. (onward air transmission) or AV2 markings, including hand written.
10. Mail with “missent” postal markings (postal service error).
11. Interruption of postal service due to unforeseen circumstances.
          a. Mail delayed, but not effected in condition or amount.
          b. Officially sealed mail damaged in mail handling.
          c. Mail from crash or fire, preferably accompanied by postal service explanation or with special postal markings.
          d. Mail returned to sender due to politics or war.
12. Censored mail (including currency control).
13. Airmail between warring nations through neutral channels. Includes under-cover mail.
14. Miscellaneous not classified above. (Original Class F)

NOTE: While these classifications of “combi-covers” are informative or instructional, they are not widely accepted or even recognized and should not be utilized in descriptions or exhibits. They are provided to give a picture of the range and scope of several types of aerophilatelic material.