Even if you trust the person, what if they were to die? The plane is now part of their estate....
That, according to my insurer, is a problem which one cannot do anything about.
The safeguard is the contract under which the trustee is unable to interfere with the trustor's (in English: beneficial owner's) enjoyment of the plane.
It might be a bit hard to sell the plane though...
Deegan - you may wish to EMAIL me your details because I know someone who went N-reg and then to Thailand, and he may be able to help you. As you say, you cannot keep an N-reg in Thailand long term. But there are other very important issues, if you are an EU citizen and transporting an N-reg across Europe - the VAT people can grab it and it has happened. Genuine foreigners can fly an N-reg anywhere in the EU but if you are an EU citizen the plane has to have its VAT status sorted. One rather crude solution is to fly it to Denmark first, chucking £5k+ at a certain lawyer, but that's pointless if it will remain in Thailand and never come back.