For those that don't know, the US Military has a special budget for things like this to try and increase recruitment, it's why you see special activities, flyovers, and booths at sporting events, it's why some leagues have teams wear patches, like the UFL or when they sponsored NASCAR's Dale Jr. In recent years they've determined those things aren't generating ~~revenue~~ recruits and have pulled back on sponsorships of teams and leagues, their UFL deal was for $11 million a year and the military alleges The Rock didn't post to Instagram about them enough and the deal didn't bring them any new recruits.
The internal report added that Army marketing officials have a "lack of confidence" future deals with the UFL can be successful. Some officials within the Army also expressed concerns behind the scenes that the UFL was not a cost-effective way of reaching potential recruits. The UFL deal cost about half of what the service spent on the NCAA, but viewership on an average NCAA game is roughly 10 times that of the UFL, according to the Army's own internal metrics.
Source: Military
So to my actual point, I don't think it's out of the realm of possibility that WWE was getting paid before and now they aren't so the shows aren't happening. It's just super easy to say they are really busy with other things right now and that this was a Vince thing and there is no Vince now. It allows them to end things without saying they were only "patriotic" for money.
EDIT: I will point out that those flyovers are necessary for the pilots, it gives them valuable training time that they need to do anyway. So next time you are at a game and a bomber or some fighter jets fly over, you've likely just been used for target practice.
This is absolutely my favorite synergy thing they have done with WB. The only thing would make it even better is if next year they do it again and have the roster do covers/or goofy versions of Christmas songs to put into it.