Michael Randall mistakenly picked up the passport of his partner Charlotte Bull when rushing in the morning to catch the plane.
Worryingly, he still managed to get past security checks at Gatwick Airport.
The 23-year-old, from Newbury in Berkshire, immediately confessed after he spotted the blunder when he landed in Berlin.
Immigration officials quizzed Michael for more than an hour before he was allowed to continue his trip on a one-day travel pass.
The couple, who had just holidayed in France, urged the airline to investigate the breach.
Michael, a technician with McLaren Formula One, told the Sunday People: “It’s outrageous I got that far.
“easyJet are meant to check the name against the boarding pass but they obviously didn’t.”
He was heading to Germany to watch a motorbike race.
The fact he managed to travel so far using a passport which has a picture of his 34-year-old partner could raise security concerns.
Charlotte, 34, said: “It was a terrible breach of security, even more so considering how scary current times are.”
She said that the passports were “mixed up while unpacking”.
An easyJet spokesman told the Sunday People it was investigating the issue as it admitted the “visual identification” on boarding should have spotted the mix-up.
This article originally appeared in The Sun and was republished with permission.