delt0r wrote: There is another problem. A FF using p+11B reaction will produce some high energy gammas. About .1% of the energy output or so, ie about 6kW of gamma in the MeV range. Even if the rate is less by a factor of 10 that is still a lot of radiation. These will need far more than a 1 meter of shielding.

This comes up occasionally. Lerner says it will not be a problem.
https://focusfusion.org/index.php/forums/viewreply/728/

delt0r wrote: Even a meter is too much for the weight of an aircraft.

You need to factor in that the shielding surrounds a very small volume (operational FF cores will be much smaller than what you see in the current setup) and that the shielding is mostly water.

Even a conservative estimate only gets you 4.3 tons shielding per core… less if you use multi-core units as described above. That’s less than the weight of the jet fuel that you won’t be needing anymore.

delt0r wrote:
I can’t see p+11B flying. It makes more sense to use a big power station to create jet fuel out of air and water.

It’ll work fine structurally. The one serious drawback is that a crash will pose a risk of releasing carbon-11… which will decay back into B11 in 9 hours but would be used to freak people out.