The plural form of aircraft is also aircraft. Is one of those odd irregular plurals, like sheep, fish, etc.

craft = boats aircraft = planes spacecraft = rockets, spaceships. The plural exists but has a different meaning: craft/crafts = skilled trades such as potters, rug-makers, carpenters, glassblowers, handmade jewellery creators etc.

oh thats new for me as well. there really are some tricky words. for the longest time I had been saying "informations" instead of information^^

And hovercraft!

Hey. It's plural form is the same as the singular. https://simple.wiktionary.org/wiki/aircraft#:~:text=NounEdit&text=(vehicle)%20(countable)%20An,aircraft%2C%20including%20helicopters%20and%20jets.