I made an X-15 like device, and I was having the same trouble you were. If you can, mount decouplers on the wingtips and then attach fuel tanks, engines, wheels, intakes and wings on decouplers, reenforce with struts and you can fly, and once up to altitude, just decouple Flypods (as I call them) and fly on. No vessel-switching or spin-outs as long as your glider thing is stable. But those 1x1 panels do not generate lift, if that's what you're looking for, use structural wings or canards. Good luck! Cheers! ~Spacejoe