I know this topic came up awhile ago, and some fans of the much-lamented pops were trying to replicate them, and their texture, in their own kitchens....
I have news from the inside!
Turns out one of my close friends (so this is not an urban myth :) ), a chemical engineer, went to college with one of the Pudding Pops creators, a food scientist...According to him, they are nothing but instant-pudding product whipped with HUGE amounts of air, then frozen...As she said, "Fast-food companies LIKE to sell air at a profit!"
So, although I know nothing about how to get the air IN, I'm betting that some of you frozen-dessert afficianadoes do...That's the scoop. He swore that's all it is!
BTW, the same scientist was partially responsible for StoveTop Stuffing.