WordNet (r) 3.0 (2006):

airmail
    n 1: letters and packages that are transported by aircraft
    2: a system of conveying mail by aircraft [syn: airmail,
       airpost]
    v 1: send or transport by airmail; "Letters to Europe from the
         U.S. are best airmailed"

Moby Thesaurus II by Grady Ward, 1.0:

46 Moby Thesaurus words for "airmail":
   PP, RD, RFD, air-express, airfreight, book post, consign,
   correspondence, direct mail, direct-mail selling, dispatch,
   drop a letter, embark, expedite, export, express, forward,
   fourth-class mail, frank, freight, halfpenny post, junk mail,
   letter post, letters, mail, mail-order selling, mailing list,
   newspaper post, parcel post, post, post day, registered mail,
   remit, rural delivery, rural free delivery, sea mail, seapost,
   send, send away, send forth, send off, ship, special delivery,
   special handling, surface mail, transmit