In article ,
says...

Would it be possible to design something like the XCOR Lynx for level
flight, with a rocket but still have a useable range?
Let's say a normal cruise speed, size and passenger capacity competitive
with a Lear Jet 23, or a Cirrus Vision.

Rocket engines are not at all efficient for cruise because they don't
take advantage of the atmosphere in any way. For subsonic cruise, you
can't do much better than a modern high bypass turbofan engine.

Jeff
--
" Ares 1 is a prime example of the fact that NASA just can't get it
up anymore... and when they can, it doesn't stay up long. "
- tinker