Former United pilot Jeff Ecklund told the Chicago Tribune that Wednesday's scheduled flight marks the end of an era that began 41 years ago when the airline first embraced the medium-range airliners as part of its fleet.
"It's like losing a best friend," Ecklund said. "We tend to become attached to these big pieces of aluminum."
Wednesday's flight will involve stops at every one of United's hubs as a celebration of the retiring airplane.
Grounding the Chicago-based airline's entire 737 fleet, along with six Boeing 747 jumbo jets, will result in 1,450 pilots being furloughed, the Tribune said.
Aerospace executive Tom Lee said Wednesday's scheduled flight should be memorable for airplane enthusiasts as well as individuals with an intense fascination with flight.
"It's got to be the fascination with flight," Lee told the Tribune. "There's something with man's desiring of spreading his wings, getting off the ground and wishing he could fly."