As Ruth is running to board her flight, she runs up to a Pan Am boarding gate, the first gate on the right after the final turn. The aircraft sitting at the gate is maroon and white. Pan Am's paint scheme was Blue and white. You would not have seen another carrier's aircraft sitting in Pan Am's gate.
When Ruth is getting ready to board, you see a Southwest Airlines Boeing 737 being towed in the background on the ramp. It is painted in the Blue/Orange/Yellow and Red paint scheme. The show is set in in 1986, but Southwest didn't change to the blue paint scheme until 2001.
When Ruth is getting ready to board, you see a Southwest Airlines Boeing 737 being towed in the background on the ramp. The aircraft is clearly equipped with winglets on the wingtips. The show is set in in 1986, but 737s didn't start getting winglets until the introduction of the NG series, which occurred in the late 90's.