It depends. Factors to consider:

* Your leg length (not overall height).
* Thick versus thin airline seats. (Thin = more room, but less padding.)
* Reclinability of seat in front of you.

You can compare seat pitch with that of airlines more familiar to you at http://www.seatguru.com . But 31" is common for economy class in US airlines.

I don't think seat pitch was any bigger in the 1990s and 2000s.