Ultimately it is a choice, and there can be a lot of reasons for it.
One thing I will say is that nobody in Hollywood ever uses the excuse "because it's just a movie." *Ever.* If you say that or even think it, you will never work in Hollywood. I'm saying this from experience - it's been a while now, but I worked on several medium-budget movies before deciding I needed to make more money than Hollywood was willing to pay me
I do still work on TV
shows, though, and have been doing that for the past 9 years.
(Most Hollywood jobs are very low paying, and irregular. You're lucky if you can make $30k per year actually working on films, unless you're somebody really well known.)
But that culture of "eh, who cares" does not exist in Hollywood. Even the worst filmmakers care about their movies and what people think of them, they're just either not good enough managers to make every shot in the film work perfectly, or it just wasn't physically possible to do it. But film is a literal medium and every half-decent filmmaker knows that - it's literally Filmmaking 101. (It was the first thing I learned in my first film class.)
I could give you a couple of good reasons for showing the wrong plane on a landing shot. The best reason is that filming all needs to be scheduled well in advance - actors have their own schedules, there's a set budget, equipment may only be available at certain times, catering is only set up for certain times (this can be a big deal! You can't have an 8 hour shoot with no food available), transportation may only be available at certain times, and outdoor light is obviously not always available. Scheduling a film shoot is like putting a jigsaw puzzle together. So if you know you need a shot of a plane landing, often the type of plane or airline it is will be the *least* important consideration - because of all the other stuff going on, you may only have a window of 10 minutes to shoot what's going to be a 10 second shot. There's no time to wait for the right plane, and nobody's going to tell an actor "sorry, we had to bump your scene so we could go shoot a plane landing for a 10 second shot, so can you come in at 6AM tomorrow?".
Often it will be a 2nd or 3rd unit that films these kinds of shots as b-roll, so they wouldn't necessarily have to worry about scheduling around actors, but they'd still have a lot of the same considerations otherwise.
Then you can ask "well, why not just use stock footage", and the answer to that is usually pretty simple - it's just not always available. There's not some huge repository of footage of every single plane from every single airline landing at all the major airports in the world at every time of day and in every type of weather that's free for licensing to anyone. There's *some*, and you do see that kind of stock footage in movies and TV
shows, but it's often the case that there's nothing available that fits the film (especially with the perpetual license terms that filmmakers need). Or, sometimes filmmakers will have no choice *but* to pick a stock shot that doesn't really fit, because it was raining the one day they had to shoot planes landing or something like that and they have to take whatever the stock agency has.
But it's definitely not the case that filmmakers don't care about stuff like this, it's more a case of them having to work around limited resources, and setting priorities. Even in big budget movies, most of the budget goes to things like paying for high priced actors and special effects, and the schedule can be even tighter than on a smaller budget film; there's still not going to be a lot of time to go out and shoot b-roll at airports.
I'm tired of being a wanna-be league bowler. I wanna be a league bowler!