Re the UA 26
To all those "Spotters" out there, the Aircraft had the structural integrity (tolerance of design scope) to embark on a 3000NM flight, allow the crew to monitor the WX at their destination and within say 30 minutes, decide to come back to the point of departure and deposit the passengers and crew for another go.
The Boeing 757 design has provided UA with an as yet unprecedented degree of operational flexibility [Edit:for its time] that will be missed when the design is superseded by lighter and in their way better airframes.
It starts to look like the 757 with its unique combination of installed power/structural integrity (as a result of the technology of its time) and fuel carrying capacity makes it a DC3 of its time. (Perhaps the 767 too ?)
CAT III