as previously discussed before I started wading through to much bull shit  we where talking air to air refueling a refueling probe will almost be a necessity these are proven systems easily to reverse engineer with two most common variants one the navy type one type used by air force a duel type probe would seem to make more sense or a common one but does the government make sense? what im saying is using a common probe would add some extra redundancy just in case one day they throw you a bone and actually help out but most of all ease of reverse engineering these space plane refueling probes will retract under the top aero cover out of the way for reentry also as previously stated the best way to refuel a space plane is your buddy's space plane this would be one of the most important collaborations to keep everyone's cost down so of course having a probe design that can be reconfigured and lengthened for pumping fuel would be desirable.  Ok your toped off and ready for the big push it all depends on what engines your packing say at first you can only get your hands on one surplus jet engine and you made it this far the max altitude you can only go so high with a air breathing jet you could try to squeeze more out by retro fitting some type after burner setup or introducing some type oxidationer like liquid nitrous highly risky and more complicated as a note im quite parcel to using a rocket that uses jet A and liquid nitrous. but say your just using a jet as your primary propulsion for now all you got so far is a very high performance high altitude aircraft but you can still launch remember those pods I was talking about there ideal for jettisoning at extreme altitude and could very well reach low earth orbit with minimal rockets either solid or liquid this methods like the poor mans stratolauncher the advantages are a little less risky for initial flight ops less reentry burn quicker turnaround. as a note lets look at some ruff expectations for these type craft all depending on configuration engines and flight geometry hopefully im looking to launch around 1000lb maybe 1500lb a striped down non manned autonomous remote control bird with a high performance duel cycle air breathing rocket using jet A and liquid nitrous might get 2000-2500lb in orbit . lets talk other options o yell this designs a modular beast designed to morph at this time your wing pack is out the main inner wings are ideal for hanging drop tanks or solid propellant ascension rockets.