For two reasons.
1 ILs - which city do I have to look at again for a new IL partner (not so important)
2 Looking for openings in game worlds, especially older ones - right now we have to manually look through the statistics page at hundreds of airports, dozens of countries to find an opening. A simple filter search of bankruptcies is available, but without the HQ of the airline it is useless in this regard. The openings on this forum is helpful, but it would really help more people get into the old game worlds if there were better tools to search (statistics page should have more as well)
This is a super easy fix, new enterprise foundings have the HQ listed in the line