Nah, that's all pretty common fare. Gravity never lies, though.
... Unless you want to take it a level deeper and start a discussion on the viability of SR taking place on a post-terraformed-post-colonized Mars, well after the RF games, and after the planet has flooded in a recent apocalypse event. Hence, the only two cities in the game both being fully-occupied islands with no other land in sight and the noir-esque return to pre-colonized Mars at the end of SR3. If that's the case, the plane in Air Steelport would be operating within its capabilities, as the player's terminal velocity would be a lot slower with lower gravity and an assumed increased air pressure due to the terraforming.
Again, not really my department nor is this an official [V] statement, but I can't resist a good conspiracy