This is very common advice, but I don't think it fits everyone's circumstance. Sure, go start with the first one that calls if you don't have multiple offers. But the implication (at least when I hear this advice) is that you're going to hang your hat there for your career.

If someone is planning to remain where they live when they are hired and it's nowhere near any major airline domicile, then commuting to pax airline X, Y or Z may be a coin toss. Sure, take the first offer you get. If they already live in a domicile city for a particular airline or are open to moving to a particular domicile city but not others, then maybe continuing to pursue their true dream airline that meshes with those relocation plans while they start with the one that calls first is the best move.

After doing the pax airline commute for a while, when I look at my commute at FedEx now there is no comparison. Anyone who has committed to career as a commuter for whatever compelling reason who is still looking for the final company where they can hang their hat needs to be trying to get hired at FedEx. IMO, there is no better place to be a commuter.