[kshacker]

Such arbitrary decisions are part of our day to day life. This is not new.

You can vote at 18. Why not 19, why not 18.1? You can drink at 21, why not 18, why not 20.5? When buying tickets, there are tickets for children and senior. When buying food, there is senior discount - in some places it is for age 55, some places for 60, well actually the numbers could be anything from 50-67 (starting age).

We draw such arbitrary boundaries every day. They could be based on statistics, or marketing, but they are part of life.

For airlines, I presume at some age, the weight/space taken starts becoming a factor, so they likely picked 2 year as a boundary in this case.

[xref]

I agree with all that. But I still think if they move the free passenger bar from 2y to 0y it will be an undetectable change in the number of flights booked