United Airlines just discounted more routes to and from San Francisco with its New Year’s sale than most carriers even fly, according to TravelZoo. Sale fares on routes to five continents start at $48 each way, based on roundtrip purchase.

JetBlue also offers a winter sale. See details below.

DEAL 1: Cheap fares from San Francisco each way. (More sale fares are available from Oakland, San Jose, Monterey, Sacramento, Chico and Fresno). Sample faires from SFO:

• San Francisco – Los Cabos – $125
• San Francisco – London – $269
• San Francisco – Honolulu – $239
• San Francisco – Tokyo -  $341
• San Francisco – Orange County – $48
• San Francisco – Tampa – $80
• San Francisco – Milwaukee – $88

Book directly with United. Use the Flexible Dates tab on the search results page to find the lowest fares. A 3-night, Friday or Saturday night stay is required. For domestic & Canada routes, book by Jan. 7 for travel on Tuesday, Wednesday and Saturday flights through March 11. Book at least 14 days in advance. For international routes, book by Jan. 12 for travel on dates through March.

DEAL 2: JetBlue winter sale through January 13, 2010. One-way flights start at $29 + taxes & fees. Restrictions and blackout dates apply. Book travel for dates by March 24, 2010, for Monday-Thursday and Saturday only.