The USN does IFR for fleet CAP right now. However, the crew runs out of
stamina after seom indeterminate time. having spent over 10 hours in an
F4 cockpit, I can tell you I really wouldn't feel comfortable engaging
an enemy after ten hours aloft. The aircraft themselves have aloft
limits; new ones do replenish the oxygen system which was one of the
F4's limits. The oil supply, with decent engines, shouldn't be a
problem. But somewhere short of 24 hours aloft the crew will be
degraded. not os bad on big birds where you can get up, stretch,
scratch, eat and drink, use the the john and maybe even get a nap. The
other bad note is the consumption of aircraft time. Each aircraft can
fly only so many hours.cycles before maintenance must be performed. So
you have a limit consisting of maintenance capablity (manhours, skills
and space) and parts availability, not to mention fuel for the birds.
As for the A10, with only IR missiles and the 30mm GAU8 and no radar
it's not much of a interceptor. Compare it to an F14 - which, alas, are
now retired to the Boneyard. As for supersonic flight in an A10 - it is
to laugh. Lord knows what the critical mach is, or what would happen
when it reaches Mcrit. It's got the general aerodynamics of a WW2
fighter, thick airfoils, fixed horizontal fins, conventional elevators,
so I imagine it would tuck (nose down) and stay tucked regardless of
what the poor pilot did until it slowed below Mcrit. Maybe some test
pilot has probed the transsonic region in it. Maybe.
Walt BJ