Sir Tim, who's airline Emirates operates almost 130 Boeing 777 aircraft - similar to the doomed jet, added the role of the Malaysian military has been 'bizarre'.
'This is a very busy part of Southeast Asia, the notion that we should not be able to identify if it is friend or foe, or we can on primary radar and do nothing about it, is bizarre,' he said.
'What would have happened if the aircraft would have turned back to fly into the Petronas Towers in Kuala Lumpur? But we identified it as "friendly"? Friendly with intent, or friendly without intent? But what was done? These are the questions that need to be asked of the people and the entities that were involved in all of this. Full transparency of that will help us to find out what went on.'
In Spaeth's article, which was published for German magazine Spiege last month, Sir Tim also claimed that 'control was taken of' Malaysian Airlines flight MH370 before it vanished.
Sir Tim said it was very important that the airline industry does not accept that the fate of MH370 is an 'unexplained mystery'.
'MH370 remains one of the great aviation mysteries. Personally, I have the concern that we will treat it as such and move on. At the most, it might then make an appearance on National Geographic as one of aviation's great mysteries. We mustn't allow this to happen. We must know what caused that airplane to disappear,' Sir Tim said.