First time visitors to Glasgow might be anticipating any number of delights, but it's safe to say that tracing the footprints of a deceased brown bear won't top most to-do lists.

Katy Carr, however, is a woman with her own agenda. The true story of Wojtek the Soldier Bear – made a private in the Polish army in 1942 and commended for his heroism at Monte Cassino – is just one of many unusual song subjects on Carr's fourth album Paszport, and she is particularly excited about her forthcoming Celtic Connections visit because "his first steps on British soil were in Glasgow. There's a photograph of Wojtek walking through the streets after he got off the boat from Naples. We have a lot in common. He was Polish and Scottish, just like me".

As you may already have gleaned, Carr is no ordinary singer and Paszport no ordinary album. A deeply emotional and beautifully realised exploration of personal roots and wartime history, it tenderly and poetically pays homage to the people who fought for Poland's independence only to see the country taken over by the Soviet Union at the end of the Second World War. Aside from a stirring hymn to Wojtek – who ended his days in Edinburgh Zoo – there are lost love stories, folk tales, laments for the 1.8 million Poles transported to Siberia and a song about the conflicted loyalties of pilots forced to bomb their own cities.

Though Carr was raised in Nottingham, her mother is Polish and until the age of five the family lived there. She remembers "having to wait in queues for things that weren't there, and picking mushrooms in the forest with my grandmother. I wanted to reconnect with Poland but as an adult I needed something to open the door. Then I stumbled on this story and it led me on a wonderful journey".

Her initial source of inspiration for Paszport was Kazik Piechowski, a 92-year-old war veteran whose story she first heard while watching television in her aunt's house in southern Poland. Though she struggled with the nuance, she realised that he was telling the story of his escape from Auschwitz.

Some detective work on Google led to nothing, but a friend later found a YouTube clip – "and that was it". Carr wrote Kommander's Car, which first appeared on her 2009 album Coquette, about Piechowski's daring escape in June 1942, a feat undertaken in Rudolf Hess's car while disguised in SS uniform. Later she made contact and found him "so open, kind and wonderful". That meeting was the basis of a documentary, Kazik and the Kommander's Car, and led directly to Paszport. The album opens with a new version of Kommander's Car and is dedicated to Piechowski, who Carr insists embodies the quietly heroic spirit of a dark era in the country's history. "He was born in a free Poland and then everything was taken away from him. He represents an entire generation of Polish people like that."

Carr has always been drawn to the 1940s and vintage aviation. Sartorially she sports a natty line in retro glamour. As a child she had a poster of Amelia Earhart on her bedroom wall and later became a qualified pilot with the Air Training Corps. After meeting Piechowski she immersed herself in Polish wartime culture, soaking up personal stories and cultural myths, visiting key locations and museums and even brushing up her language skills at university in Krakow. At the start of all this Carr's Polish was rudimentary; now she has written and recorded almost an entire album using it. "I'm convinced the ghosts were telling me what to write," she says. "With some of the songs I was sitting on a bench in Warsaw and I just started to sing them out of nowhere."

She was deeply affected by the whole process. "I spent about two years crying," she says. "The cruelty was so unnecessary and heartbreaking. They are incredible stories but completely untold, which has made Poland think its history isn't valuable." The music on Paszport accentuates the album's themes, fusing klezmer, gypsy jazz and classical music to create a contemporary European folk music. "I wanted it to sound like what the partisans might have played in the forest, but with 21st-century technology," she says. "It needed grit and passion, I didn't want too clean lines. I wanted it to have a raw edge."

I wonder how Piechowski's generation of Poles – and subsequent ones – feel about an outsider stepping into their history to articulate their often painful stories. "It's been so positive," says Carr. "It's fantastic for the people who inspired it, their stories are finally being heard. It's a great honour for me. It feels like I have a duty to do this really well for all the people who didn't have a voice in those times." Yet she also hopes Paszport has a wider resonance for all disenfranchised people, whatever the specifics of their stories. "I don't see this record as something stuck in time," she says. "It translates to a number of different cultures and places right now. I've had people writing to me from Afghanistan, Russia, Costa Rica, Africa ..."

Carr promises her next album will explore her Scottish roots – her paternal grandfather is from Dumfries – and squeals that playing Celtic Connections is "a dream come true. I've done Poland and now I need to do an album about Scotland". She says she fancies writing a song about Queen Mary's bath house. Is there room for a bear?

Katy Carr plays Oran Mor on January 26 as part of Celtic Connections. Paszport is out now on Deluce