i'm with (and can't believe i'm saying this) buck. jet fuel will burn upwards to 1000c (generally 800c). that is not hot enough to melt steel.
however, a jet fueled combustion engine can reach temps of 2000c. compartmentalized internal combustion, fed precisely, and cooled. it's like the engine in your automotive vehicle, a cooling system is needed to moderate temperatures generated from compartmentalized internal combustion.
a jet engine's exhaust can become hot enough to melt steel.
jet fuel with no injection and forced air (JET ENGINE) cannot burn hot enough to melt steel. steel melts at approximately 1400c.
and though with giant turbines forcing air to make a hotter combustion (more compression), even this cannot CUT steel like thermite. steel will lose approximately half it's tensile strength at 650c, but won't melt, and won't buckle unless load is too high (which is against building code).
pretty sure all this info is on google, btw, just in case you'd like to read for yourself.