In 1941, Joseph “Mac” McConnell, Jr., a private in the Army medical corps near Fitchburg, Massachusetts, who aspires to be an airplane pilot, hopes the Army will send him to flight school. Mac goes AWOL to take private piloting lessons, but while flying with his instructor, he realizes that military police are waiting for him at the airport. To avoid arrest, he parachutes out of the plane and then hitches a ride with teenager Bob Brown. After eluding Mac’s pursuers, Bob takes him to his home in Fitchburg, where he introduces Mac to his mother, young brother and sister Pearl, whom Mac nicknames “Butch.” When the military police track Mac to the house, Mac hastily exits through a back window and returns to the base, where his superior, Sgt. Sykes, sentences him to the stockade. Wanting to see Butch again, Mac sneaks out and returns to the Brown home and later, after a brief courtship, proposes to her at a boxing match. Sykes is reluctant to give the irresponsible Mac permission to marry, until he meets Butch and realizes that she will be a stabilizing influence on him. Trying to help the young couple, Sykes arranges for Mac’s promotion and transfer to a medical school in Texas, but the transfer order comes through on the McConnells’ wedding day, thus preempting their honeymoon. The couple moves to an inexpensive apartment near the Army base, but Mac and his teachers soon agree that he belongs in flight school. When he is transferred to Washington state, Butch, who is pregnant, returns to Fitchburg. During his leave at Christmastime, Mac tries to hitchhike across country, but he runs out of time halfway there and has to return without seeing her. When he arrives at the base late, he is punished with sentry tour. Forbidden to contact Butch, Mac learns about his daughter’s birth from friend and fellow student, Ty Whitman. After completing school, Ty is chosen to be a pilot, but the disappointed Mac is assigned to be a navigator. Later, while fighting the Nazis over France, Mac and his crewman on a B-17 aircraft are attacked by a new German jet plane and after crash landing, are rescued. After World War II, Mac, trying to forget his dream of flying, is miserable at his desk job in Nebraska. When Ty tells him about the Army’s recruitment of experienced fliers for a new jet corps, he volunteers. Reluctantly agreeing with Ty that Mac was “born to fly,” Butch supports Mac’s decision, but fears for his safety. After training, Mac makes his first solo flight on one of the new jet planes, while Ty, radioing from the ground, talks him through the terrifying experience of flying at supersonic speed. Mac is transferred from base to base with his family, which eventually includes another daughter and son. Before he is sent to fight in the Korean War, Mac takes Butch on a picnic in Apple Valley, California, where he has bought property. While he tells Butch of his plans to build a house there when he returns, planes passing overhead fly in the “missing man formation” and Mac explains that the pilots are honoring a colleague who was killed. In Korea, Mac helps to rescue men on a downed aircraft in the middle of enemy territory. During another mission, his plane is shot down over the sea and he must parachute to safety. Mac distinguishes himself by gunning down enemy aircraft, which are called MiGs, setting a record for the most hits. After downing 15 MiGs, he is named the first triple jet ace in history, but after shooting down his 16th, Ty and his superiors fear that he is getting tired and reckless and transfer him stateside to train new pilots. In the States, he is given a hero’s welcome and meets the president. When he and Butch return to Apple Valley, their neighbors, who are proud that the hero has chosen to live in the area, present the family with the keys to a house that was specially built for them. After they settle in, Ty, who is now a colonel, asks Mac to take a job testing new jets. Mac is eager, but Butch, concerned about his safety, demands that he refuse the offer. However, she changes her mind, and Mac begins testing the new F86h. Mac flies the plane faster and faster, despite Ty’s warning to slow down. When Mac reports that the controls on the plane have frozen, Ty radios Mac to bail out. Mac, believing that he can regain control, stays aboard and perishes when the plane crashes. Ty immediately goes to the McConnell home to tell Butch about Mac’s death, but seeing planes in the missing man formation overhead, she has already realized what happened. Months later, Ty takes the bitter and still-grieving Butch to the base. As they watch the new test pilot check out modifications prompted by Mac’s accident, Ty says that Mac’s death will save the lives of many men, and Butch agrees that nothing about Mac was wasted.