Here is a test aircraft that carried a reactor (not to power the plane, but to test the reactor while airborne) I had a boss who worked in radiation safety (health physics) for the project. He was involved in material tests that were carried out in Georgia. It was interesting talking to Bob Boyd about how the radiation would kill the tops of trees that were higher than the shield mounds around the radiation source they used to test aircraft parts. Here is a link about the US nuclear airplane project. Nuclear aircraft
I have heard that the interesting thing about those reactors designed for the nuclear aircraft was that they had a positive alpha (i.e., positive reactivity feedback for increasing reactor power). You couldn’t license one of those today (for good reason). The other was that the final design had so much shielding there was much space of lift capacity left for cargo. Not terribly practical on balance.
Operation TIMBERWOLF ?..............