This is a very wild idea to me and I don’t think that many people would get behind the idea of an aircraft powered by a conventional nuclear reactor. However, if it were a new kind of nuclear energy that produces little radiation the support for a massive aircraft powered by a reactor using low energy nuclear reaction or LENR technology might make such an aircraft possible. LENR has been researched for decades and according to NASA Langley energy expert Joe Zawodny experimental evidence has proven LENR might be an extremely clean energy source.
The hope is that a LENR reactor might be fitted inside an extremely large aircraft that would stay in flight on a semi-permanent basis. The aircraft would fly using its LENR power plant with a normal chemical fuel reservoir for backup energy. The aircraft in the concept drawing above has two landing strips on its back. The flying machine has such a massive size that other normally sized aircraft could take off from the ground, land on the back of the giant LENR aircraft and then fly close to their destination.
Once near their destination the conventional aircraft could take back off from the back of the giant LENR machine and then land on the ground. The thought is that an air transport scheme like this could save 40% of the fuel required for a conventional flight on a 1000km route and on a longer 10,000km route; the savings could be as high as 85-90%. That sounds pretty good to me, but we have a long way to go before a LENR aircraft can prowl the skies. The main problem is that so far no LENR device has been demonstrated that can be turned on and off at will.