I remember working for the airlines, it could vary what we could give out to the kids on board. As a mom, too, one flight my kids would get cool giveaways and not on the next... so variable.
One criteria to how "kid-friendly" an airline is, comes down simply to staffing. I used to stand in line with some of those armies of Flight Attendants in the crew line. We were coming off the same model of aircraft but they'd have 1/3 more bodies in uniform. Middle Eastern and Far Eastern companies were especially good with this. Easy to be attentive with more hands to help!
I also want to point out a few more important points when it comes to flying with children. It can be frustrating to fly with a company that takes your gate-checked items, like strollers, and makes you pick them up at baggage claim at your final destination, forcing even solo mom flyers with multiple children like I was, to negotiate large connection airports without a stroller. It can be annoying to fly as a parent and not be allowed to use our own car seat. Or having to jump through a bunch of hoops in order to book a seat for an under-2, or a special meal, or a situation where the child flies out with one family member and back with another, is also a headache. Forget car seats. What about making it clear what their bassinet policy/bulkhead seating policy is?? I hate getting on a flight and seeing all adults in the bulkhead and seeing families squished in middle seats with lap babies.
So an airline, in my book, needs to do more than just hand out goodie packs to win me over as a flying parent!