... you can't compare the two [rail and air] validly because the market conditions are so different.....
In that case, I agree with you - there is not much of a connection between the two.
As a slight aside, I have not actually seen much straightforward competition between airlines. I fly to Poland once or twice a year, and can not think of a single airport-to-airport route served by more than one airline. The logistics of using an alternative airport at one end or the other usually means there is only one realistic choice unless you happen to live in or near London, where there are several airports within easy reach.