ssto

wouldn't the most simple ssto (single stage to orbit) be a aircraft with jet engines under wings and rocket engine in the back of aircraft, 

all engines using methane from the same fuel tanks inside aircraft

or aircraft with combined ramjet and jet engine under wings and rocket engine in the back of aircraft, 

all engines using fuel from the same fuel tanks inside aircraft

or aircraft with combined jet engine and rocket engine under wings 

and ramjet engine in back of aircraft with air inlets for ramjet in front of aircraft, 

all engines using fuel from the same fuel tanks inside aircraft

when jet engine, ramjet engine and rocket engine are combined 

and functions, 

then fewer engines would be needed on aircraft, 

all engines using fuel from the same fuel tanks inside aircraft