Interesting comment about using Verizon at the airport. I made about ten calls from various places at UA's terminal in SFO last week, on my Verizon Motorola V60. Full signal strength no matter where I was (baggage claim - Wed. 8am, RCC - Thur. 5pm, near Gate 83 - Thur. 6pm).
Suspect Verizon was just giving you lip service.