$121+: US fares (round-trip) within the next 30 days Through fall
Major Airlines

$89+: Fly to/from Denver & W. Coast cities (one-way) Through Oct 30
Southwest Airlines

$141+: Low weekend fares to Las Vegas (round-trip) Through September
Major Airlines

$69+: New routes to Seattle via LA & SF (one-way) Through fall
Virgin America

$198+: Midwest fall & winter flights (round-trip) Through Feb 11, 2009
Midwest Airlines

$156+: Thanksgiving weekend flights (round-trip) Nov 22–29
Orbitz

$3+: Airfare sale to/from US cities (each way) Sept 5–Nov 20
Spirit Airlines

$125+: Labor Day fares to US cities (round-trip) Aug 29–Sept 1
Major Airlines

Private jet holidays around the world
Shermans' Review

$99+: Bay Area flights from Phoenix (one-way) Through Jan 9, 2009
Southwest Airlines

$79+: Discount fares to Florida beaches (one-way) Sept 1, 2008–Jan 9, 2009
Southwest Airlines

$135+: Early booking on holiday fares (round-trip) Through December
Major Airlines

$59+: Autumn airfares to/from US cities (one-way) Oct 1–Nov 19
Southwest Airlines

$246+: Las Vegas flights via Atlanta (round-trip) Through fall
Frontier

Up to 50% off: End-of-summer fares (round-trip) Through fall
Major Airlines

$91+: Discount domestic fall flights (round-trip) Through fall
CheapOair

$49+: Low airfares within California (each way) Sept 2–Dec 18
Southwest Airlines

$140+: Low weekend domestic fares (round-trip) Through September
Major Providers

$206+: Last-min fares to/from US cities (round-trip) Through August
Major Airlines

$75*+: US wknd e-fares from 50+ cities (each way) Aug 29–Sept 2
United

$395+: Hawaii fares from 15+ cities (round-trip) Through fall
AirToHawaii

$19+: Rock-bottom fares to/from US cities (one-way) Select dates through fall
JetBlue

Under $200+: US fares w/fees & taxes (round-trip) Through fall
Major Airlines

Ending Soon -- Fall Travel Sales from $56*
Shermans' Review