As manfromuncle described, if the company has sold its assets and has no money there is little that you can do. If they no longer own/operate the helicopters then what are you going to fly ?
Instead of a winding up order you could try the small claims court. This route is less expensive (£100 or so to put your case and then another similar fee for enforcement). However the most aggressive utcome of this is that the court sends in balifs and if they have no assets to seize then you have wasted your time/money.
Sadly, if a limited company runs out of money there is little that can be done (unless there has been some illegality and you have grounds to sue a director). If you have paid upf for hours in advance then you have done little more than lent them money.