Tapit is known as a source of stamina, having sired Belmont Stakes winners Tonalist, Creator, Tapwrit and Essential Quality, and also tends to pass on a "strong-willed disposition".
[7] He later suffered a hoof crack that interrupted his three-year-old season and then a strained hock that delayed the start of his four-year-old campaign.
"[8] Flightline began his career on April 24, 2021 at Santa Anita Park in a maiden race for three-year-olds and up over a distance of six furlongs.
He bumped with one of the other entrants at the start, but kicked clear and then extended his lead around the turn to win easily by 13+1⁄2 lengths in a time of 1:08.75.
[9] He earned a Beyer Speed Figure of 105 and was named a TDN Rising Star by The Thoroughbred Daily News.
Flightline pressed the pace from outside, went to the lead midway around the turn and then opened up under mild persuasion by Prat.
[5] For his final start of the year, Sadler pointed Flightline to the Grade I Malibu Stakes at Santa Anita Park on December 26 over a distance of seven furlongs.
"[12] Flightline was awarded a Beyer Speed Figure of 118, the highest number earned by any horse racing on dirt in North America in 2021.
[5] Flightline was expected to begin his four-year-old season in March 2022 but suffered a minor issue to his hock, causing another setback.
Sadler was not concerned about stretching the horse out to a distance of a mile, noting Flightline had been full of run at the finish of each of his starts.
[13] He went off as the 2-5 favorite in a field of five that included Speaker's Corner (Carter Handicap) and Aloha West (Breeders' Cup Sprint).
"[14] Flightline made his next start in the Pacific Classic at Del Mar on September 3, stretching out to 10 furlongs for the first time.
Although some were concerned about potential stamina issues, Flightline went off as the heavy 3-10 favorite in a field of six that also included Dubai World Cup winner Country Grammer.
He was bumped on both sides while leaving the starting gate but quickly settled into stride, pressing the early pace set by Extra Hope.
Running freely, Flightline continued to open up his lead, winning by 19+1⁄4 lengths over Country Grammer.
[20] Flightline finished his career with a convincing victory in the $6 million Breeders' Cup Classic on November 5 at Keeneland.
Flightline chased the 2021 Breeders' Cup Dirt Mile winner Life Is Good for most of the race, with the rest of the field far behind.
"[21] He echoed Bud Delp, the late trainer of the great Spectacular Bid, in saying that Flightline was "one of the best horses to ever look through a bridle.
[17][24][25][26] The connections of Life Is Good said that they had decided to make Flightline "earn it"[6] by going to the lead and setting a fast pace.
"I felt [Flightline] every step of the way, just tried to get away from him and I couldn't," said Life Is Good's jockey, Irad Ortiz, Jr. "I know I'm going fast and I said let me look again down the backside and he’s there.
His final rating of 140 ranked equal with Frankel as the highest ever awarded by the International Federation of Horseracing Authorities.
[32] Lane’s End announced Flightline’s retirement on November 6, 2022—the day after he won the Breeders’ Cup Classic.
[36] Agent Fred Seitz, owner of Brookdale Farm in Versailles, Kentucky, placed the winning bid of $4.6 million on behalf of a client who did not wish to be publicly identified at the time.