ALPA is the only AFL-CIO affiliated union with more registered Republicans than Democrats.

Chance of the NMB releasing the UAL/CAL pilots under BO = 50/50
Chance of the NMB releasing the UAL/CAL pilots under a Republican President = 0%

This is what it comes down to. ALPA member can keep supporting Republicans who NEVER side with labor, or side with politicians who at least sometimes side with labor.