United 757-300

The Boeing 757-300 is an extended version of the (increasingly less) common 757-200 model.  It 23 feet longer than the standard model and looks silly in person, almost like it's too stretched out to work.  It also may be the 757 type to stay in airline service the longest because it seats up to 280 in an all coach design and has no planned replacement.  Airlines are trading in their 757-200 models for 737-900ER's that are much more fuel efficient, though seat 10 fewer and have shorter range.  There is no easy replacement for the 757-300, there isn't a 737 planned that can match the extra 31 or more seats.  Just be careful next time you fly a 757-300, Delta squeezes 11 more seats on their airplanes than United.

United Airlines 757-300