Hello,
After watching some videos I decided to try to build an aircraft capable of launching a rocket. I installed a rocket fuel tank to on the aircraft itself to provide the fuel to the rocket via fuel lines until separation, but it doesnt work. The rocket keeps using the fuel from its own tanks and nothing from the tank in the aircraft. I checked orientation of fuel lines, detached and reattached the rocket and moved the fuel lines to attach to different tanks, and even the engine they are supposed to feed, but to no avail.
Here are some images: