Sounds like you’re talking about the price elasticity of demand. You describe airline travel (at least for personal economy class flights) to be fairly inelastic, meaning that if the price rises even a little bit, a lot of people will just drive or not take the trip. That certainly rings true to me. I recently bought US domestic flights home for Christmas, and I certainly chose the absolute cheapest flight that fit the schedule and had less than 2 hours of layover. The price was already brutal, and I felt like I was very near the top of my price tolerance.
But I feel like the Lyft/Uber mode of transport is generally more spontaneously and is therefore generally more elastic. Sure, there are undoubtedly some inelastic use cases, like regular commutes, but there are also some very elastic use cases, like a ride home from the bar or a rescue from the rain. I am definitely interested to see how the breakdown of these different use cases turns out to be, but for me and my friends and peers in the SF Bay Area, the latter use case definitely dominates.