Honestly quiet enjoyable and great tension throughout but yes there's no escaping some of the plot holes. Enjoy it for what it is though.
Some stupidity to highlight (in no specific order):
1. Idris texting his ex wife "there's been an incident". Unnecessary ambiguity used as a plot device
2. Police officers responding to a 999 distress call casually leave when suspicious cleaner opens the door and says all good nothing to see here
3. Iraqi ground control thinking it's fine for i) plane to have no response for 5 mins, ii) female copilot to impersonate the male pilot, iii) male pilot coming back after a toilet break and saying nothing to see here
4. The whole Hungary (or was it Romania?) landing sequence with the copilot.
5. Casually flying over west London with imminent threat of pilot suicide and god knows how many deaths because foreign secretary tells PM to ignore protocol
6. Idris attacking a hijacker, being locked up and left alone with another hijacker, then being allowed back in his seat because nothing to see here hijackers have memory of a goldfish
It's quite fun to go on and I could list a dozen more but that's part of the fun of watching it.