Our journey on Earth is boot camp for the soul. Every person receives a custom-tailored live-fire exercise from God to specifically designed to polish the unique dark spots in his/her soul. Every soul is different, which is why we each face different challenges and life experiences. Suffering and adversity should be welcomed, because they are the only path toward casting off our worldly weaknesses and looking to the light of God with an unblemished soul. All in accordance with God's plan.
Except, that guy, Lt Col Bud Holland, was a reckless, arrogant asshole who considered himself invincible due to his skills, which he judged to be superior to other pilots. Also, he took the life of two others as well. One of them, the squadron commander, was a true American hero, who did the only thing within his power to protect others when wing leadership refused to ground the guy. He decided that HE would be the only on would be the only one to fly with Bud, and paid for that courageous decision with his own life.
Barrel roll is not that difficult if you have enough airspeed, especially if you don't give a shit about exceeding aircraft structural limits or the energy state of the aircraft once the maneuver is completed. A monkey could do it. Landing? Not so much.
Also, mechanics know how to start the engines, are aware that every aircrcraft contains a checklist for other systems, and many are trained to o do engine runups and even taxi aircraft around on the airfield. Takeoff takes practice to do well, but not that difficult to do successfully if the winds aren't too crazy.