Cheesy and common to the times, still there's a nostalgia to watching these old flicks from the 70's, it was worth the watch for that alone. A little snapshot of the bad/campy/predictable TV of the day, but somehow fun anyway.
As for holes and errors in the scenes, one could pick apart all the discrepancies, and most been done here. I'd add that I've never been on a flight, nor seen one from those days where all the seats are oriented backwards to the nose of the plane, not to mention the rest of the seat layout, fanning in towards the aisle as they do. Maybe they did, but first class, flying backwards the whole way? Might make some people more ill if they're prone to that.
Some mention the variation in quantity of passengers in some scenes (coming and going of passengers), but there's the bathrooms, and not staying in your seat would be normal back in the good old days when a lounge was available, though they showed the lounge mostly empty when shown at all. (I'm all for bringing the lounge back, especially for long flights). "Skyjackings", as they were called, were in the news a fair bit in those days, yet dogs seemed to do just fine in deterring trouble, no need for today's excess. If only people could watch the news these days with as discerning an eye for discrepancies as they do with films, they may notice a few things. At any rate, a good little film if you want the flavor of how that genre of TV was back then....