I really need some help, I'm stuck in flight mode on the private server and I can't do anything, please someone help me !! :'(

Try to logg out and rejoin if that don't work then I don't know. Is there lagg? 

What you do is you go to the monitor and you select Moon then you Re materialize then go back to Earth and De materialize  then Re materialize it worked for me every time. Hope this helped!

If that does not help then screenshot your tardis cords and hope for the best! To get to your tardis Cords if you are on the Platform Windows its, Windows Key + R the go to %appdata% then go to .minecraft then go to screenshots! 

I tried to disconnect and it doesn't work, and by flight mode, I mean when you fly with the flight panel, so actually, I'm a tardis exterior ^^' I need some admin's  or modo's help I think

What you do is you land on the floor and you wait until a message in the top right corner says L CTRL the push the left ctrl button and it should work! Hope this helps

Or enjoy your life as  Tardis. JK xE xE xD

I think I know a fix for this - a staff member has do ban/kick you, then when you rejoin they smite, drop or kill you. This usually sets you back to normal. What time will you be on at so I can come help?

I can now :)

Great!!

By "I can now" , I mean that I can connect now, not that I'm unstuck ^^'

Oh well you have to go ask a Staff member to help you!