I would like to present the first (and to my knowledge only) air-space ssto fighter, the X-Rei Firestorm and attachable warp ring. There is also a basic SSTO version, and a per-combined fighter and warpring provided for ease of use. (you'll have to hack the combined version into orbit but you won't have to fly it up either)
Hybrid starfighter and SSTO, uses advanced propulsion and antimatter reactors. It's capable of keeping pace with any fighter in low atmosphere on Kerbin and it's capable of flying with unlimited time in most atmospheric bodies in the Kerbol system but will require re-configuring cyro-tanks to store the most optimal fuel available. It requires refueling or an attachable warp drive for interplanetary travel.
It's a match against even the P-1187 Super Dreadnought
The name it two references to X-COM X-ray being the nickname of the aliens given by the soldiers and Firestorm after the best fighter craft available in the game.
Uses the following mods: KSP Interstellar Extended, KSP Interstellar Fuel Switch, KSP Interstellar Fuel Switch Core, Kerbal Joint Reinforcement, Heat Control, Tweak Scale, Community Resource Pack, BD Armory, and last but not least Module Manager.
Basic design and Warpring do not require BD Armory
All mods current as of December 17, 2017
December 19th, 2017, added EX version, which adds more missiles
Controls
1 - Plasma Engine Toggle
2 - Thermal Engines Toggle
3 - Engine Fuel Toggle
4 - Air Intake Toggle
5 - Docking Port Shield Toggle
6 - Undock or decouple
7 - ECM toggle
8 - AI Autopilot Toggle
9 - Fuel Scoop Resource Toggle
0 - Fuel Scoop Toggle
2 - Thermal Engines Toggle
3 - Engine Fuel Toggle
4 - Air Intake Toggle
5 - Docking Port Shield Toggle
6 - Undock or decouple
7 - ECM toggle
8 - AI Autopilot Toggle
9 - Fuel Scoop Resource Toggle
0 - Fuel Scoop Toggle
~ Maximus Light