We do not prescribe diazepam or similar drugs for fear of flying, for the following reasons…
Diazepam is a sedative, which means it makes you drowsy and more relaxed. If there is an emergency during the flight it may impair your ability to concentrate, follow instructions and react to the situation. This could have serious safety consequences for you and those around you.
Sedative drugs can make you fall asleep, however when you do sleep it is unnatural non-REM sleep. This means you will not move around as much as during natural sleep. This can cause you to be at increased risk of developing a blood clot (DVT) in the leg or even the lung. Blood clots are very dangerous and can even prove fatal. This risk is increased with the length of the flight.
Whilst most people find benzodiazepines like diazepam sedating, a small number have paradoxical agitation and aggression. They can also cause disinhibition and lead you to behave in a way that you would not normally. This could impact on your safety as well as that of other passengers and could also cause legal implications.
According to the national prescribing guidelines doctors follow (BNF) benzodiazepines are contraindicated (not allowed) in treating phobia. Your doctor would be taking a risk by prescribing against these guidelines. They are only licensed short term for a crisis in generalised anxiety.
Diazepam and similar drugs are illegal in several countries. They may be confiscated, or you may find yourself in trouble with the police.
We appreciate that fear of flying is very real and frightening. A better approach is to tackle this with a Fear of Flying course run by the airlines.