You might be used to flight disruptions due to staff strikes and computer glitches but some unfortunate passengers have encountered more baffling reasons.
It seems surreal but everything from a weird smell and a mouse on the plane to missing crew and cutlery have caused delays or cancellations in recent years.
Some holidaymakers have even had the misfortune to see their travel plans waylaid by drunk or unruly passengers.
These unusual reasons for delayed flights are in fact actual claims processed by flight compensation company EUclaim between 2016 and 2015.
One of the most recent examples was a Ryanair flight from Malta to Endhoven in July this year - flight FR3475 was delayed for 24 hours due to "insects on the plane" according to the claim.
Another claim, which was processed in September, was relating to an incident that took place back in 2011.
Passengers travelling on Scandinavian Airlines flight SK945 from Stockholm to Chicago ended up being delayed after a mouse was spotted by the cabin crew.
The flight ended up being delayed for over three hours while the crew tried to apprehend the rodent.
Missing items is another reason for delay.
According to EUclaim, they processed a claim request for a Thomas Cook flight from Cancun to Stansted, which was delayed due to missing cutlery.
Adeline Noorderhaven, UK Manager of EUclaim, said: "I had to re-read the claim form to make sure I was reading right, but our client was spot-on!"
In August a Thomas Cook flight from Cancun to Stansted was delayed because of "missing cutlery".'
Missing crew has also delayed a flight.
Easyjet flight U26771 from Belfast to Amsterdam on June 25 was delayed for precisely this reason according to EUclaim.
Ms Noorderhaven commented: "While some of the reasons for delayed flights are undeniably comical, we know it can be hard to see the funny side if it's your flight that's delayed.
"Waiting over three hours because there's a mouse loose on the plane can be unnerving as well as frustrating!"
She added: "These types of incidents should not be happening and it's the airlines' job to make sure unwanted animals and smells don't get on board in the first place.
"Whatever the reason for the delay may be, all passengers are entitled to compensation - should they be forced to wait three hours or more'.
MailOnline Travel has contacted the airlines with delays listed for comment.
OTHER REASONS WHY FLIGHTS MIGHT BE DELAYED
Flights can be delayed for something as small as a missing pack of paracetamol in the first aid box.
Part of this is down to a Minimum Equipment List (MEL), which every aircraft must have.
The MEL contains a check list of everything the plane must be equipped with before it's permitted to fly.
If the MEL stipulates, for example, that all three first aid boxes must contain a pack of paracetamol but one box is missing a pack, the flight will be delayed until a replacement pack can be found.
In some cases, the issue can be quickly rectified but in other cases, it can take a substantial amount of time.