This one is over the lees of late spring leisure travel. And it's probably more of a skirmish than an all-out war. JetBlue is offering one-way fares as low as $49 for flights on Tuesdays and Wednesdays through May 23. There is a 7-day advance purchase required, and a blackout period for Boston (4/12/12 – 4/22/12), and you must purchase by midnight tonight. Here are all the other terms.
Southwest is offering one-way fares as low as $69 and AirTran $81 for travel on Tuesdays and Wednesdays through June 6. There is a 14-day advance purchase required and purchases must be made before March 9. Here are the terms for Southwest and AirTran.