If you get an A340-300 best not to look out of the window if you get nervous as the engines are so small you'll wonder where the rest of them are. Due to lack of engine grunt take off run will be longgggggg and you might also wonder when the air part of the journey is going to start.

If you get nervous then education is the answer. Look up the safety records of the airlines you intend flying on (BA and VS are uber safe). Flying Air Chance or Air Afrique might produce different results!

Finally, the moment you decide to pay for the ticket is the moment you should stop feeling nervous.