Can I purchases food on the plane even if I haven't booked food?

Yes they do there is a plane magazine and it has a variety of hot and cold food and drinks

They don't even really offer pre paid food anymore as they do a range of sandwiches, paninis and pastas

However it may be better to buy food before the airport as it is VERY expensive

Also they will come up and down with the trolley offering shopping and food but if you miss it you can use the call button and request food if you missed it or weren't hungry at the time

Hope this helps

It depends on what airline you're flying. Here in the U.S., they only offer food service in first class. All others you can get a $5 cookie (it wasn't very good in my opinion!) or a box of crackers and cheese for an outrageous price and there was something else, I can't remember what it was. They do still offer complimentary sodas tho!

The best suggestion I can offer is to bring a bag lunch with ya. Check with your local airline security regulations to see exactly what you can bring as far as food. You can always just buy something in the airport and bring it on board with you. Thats what most folks here do.

I hope this has helped and Happy Travels!