[goodcanadian]

That was part of the rationale behind the space shuttle in the first place. It was to create a space plane with aircraft-like operations in order to fine tune processes and technology to bring down the cost of space flight. Unfortunately, NASA never managed the operational cadence required, in part, because of the per-flight cost (which was, in turn, high, in part, because of the low flight cadence). It was a fine idea, but it didn't work out so well in practice.

[bsder]

It also didn't help that the design was compromised.

In order to get funding from the miltary, the shuttle had to be able to switch to a polar orbit which is why it had those stupidly large engines that serve no purpose otherwise.

If you get rid of that, you actually can design a reusable space plane.

[lupusreal]

Turns out, making something look like an airplane doesn't mean you can treat it like an airplane.

[dotancohen]

The space shuttle's appearance has little to do with its flight cadence - the airplane-like flight cadence (and thus, airplane-like reliability and cost) just never manifested. Especially after January 1986.