Jet Blue's FF program requires approximately 4 transcontinental round trips plus one more (one way or round trip) flight booked on-line within one year (each earned point expires one year after earning). If you buy with a Jet Blue American Express card, you may be able to extend point expirations. No FF partners other than the American Express card. No elite status, all economy class. Jet Blue uses A320 planes for transcontinental flights; they have 34" seat pitch and personal TV screens. There are 38" seat pitch seats for an extra charge.

Virgin America's FF points are based on fare paid. Award costs vary by the flight and class selected. Virgin America has first class, and economy class with 32" to 34" seat pitch and personal TV screens.

United's FF program is based on mileage. United gives 2,419 miles each way for SFO-IAD. You will need 5 round trips and 810 additional miles to make the 25,000 domestic economy award threshold. 25,000 elite qualifying miles in a calendar year gains elite status, including free Economy Plus seating with 35" of seat pitch, versus 31" for regular economy (but no personal TVs for either on most planes). Miles for redemption of awards expire if there has been no activity for 18 months in the account, but United has numerous partners (e.g. on-line shopping, as well as Star Alliance airlines such as US Airways and Air Canada) that can be used to create activity in the account.

United can be a rather unpleasant experience for a non-elite, limited to the worst seats and with long check-in lines if you are unable to check in on-line. Elite status passengers get a number of perks that can make flying on United more pleasant.

The main other airline in the SFO/OAK/SJC area is Southwest, but it does not appear that they have non-stops to the DC area (BWI). Alaska has a west coast regional presence, and may be useful for mopping up miscellaneous miles (has mileage partnerships with both American and Delta, even though American and Delta do not have mileage partnerships with each other).