Lenesha Riley, 33, took an Easyjet flight from London Luton Airport to Berlin on 17 January, as first reported in the Daily Star.
Despite ground staff scanning her documents, the error was not picked up until she reached the German capital.
"I opened it, saw my son's face and my heart sank," she told the BBC.
Mother-of-two Miss Riley, a student at the University of Westminster, had taken a weekend break with her mother and a friend after her exams.
She said airline ground staff at Luton "scanned the passport at the gate, checked my boarding pass and gave them back to me".
"I was in the queue at border control in Berlin and opened my passport ready when I was two people from the front," she said.
"I saw my son Josiah's face and thought 'no way' - my heart sank - my short break is over before it starts."
She was able to continue her weekend break after her brother sent a photo of her passport from her home in New Cross, south-east London.
"Security measures should be stronger - even coming back through Berlin they check your passport at departures. It should happen everywhere," Miss Riley said.
A spokesman for Easyjet said Miss Riley had "submitted the correct details online" to gain access to her boarding pass, but added "the additional visual check carried out prior to boarding should have picked up the passport issue".
In a statement, a London Luton Airport spokesman said "at no point was security at the airport compromised".
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