air letter

single sheet of light paper folded to form a letter that may be sent cheaply by airmail 航空邮笺（单页薄纸摺成的航空信件, 邮资较廉）.

AIDS, ail, aileron, ailing, ailment, aim, aim at, aim for, aimless, aimlessly, aimlessness, ain't, air, air base, air brake, Air Chief Marshal, air commodore, air force, air hostess, air jet, Air Marshal, air pocket, air pump, air raid, air rifle, air speed, air terminal, air traffic controller, Air Vice Marshal, air-bed, air-bladder, air-conditioned, air-conditioning, air-cooled, air-cushion, air-flight, air-hostess, air-raid, air-resistance, air-sea,