"I'd like to see Borussia Dortmund get to Wembley," said one crew member. "It's nice to see the underdogs win. It'd be good to have a David versus Goliath final."
Interesting. There we were en route to the home of last season's Bundesliga champions, who attract more than 80,000 people to their home games and we're talking about them as underdogs.
It's not an uncommon perception. I spoke to Sky Sports commentator Niall Quinn earlier this week and he also described Dortmund as "the outsiders" when pitched alongside Barcelona, Real Madrid and Bayern Munich.
But is this fair? Have Borussia Dortmund not earned the right to expect a place at the top table of European football rather than feeling like gatecrashers at the dinner party?
When you step inside the Westfalenstadion on the day before a Champions League semi-final, it certainly feels like you're in the home of a European giant. It's an almighty stadium that will welcome only 65,000 supporters for the visit of Real Madrid on Wednesday night, down on the usual 80,000 due to the removal of standing areas in the iconic Sudtribune (South Stand).
Last season, only Barcelona attracted a higher average attendance than Dortmund and their fervent fanbase ensures the team will rarely be fazed on the biggest stages. For proof of that you only have to look at their display in the group stage of this year's competition when they were thrown into the unenviable "group of champions" alongside last season's title winners from Spain, England and Holland.
The outcome? Borussia Dortmund remained unbeaten in six games against Real Madrid, Manchester City and Ajax and topped the group with four wins and two draws.
The trophy cabinet, on display outside the press centre, would certainly be the envy of many clubs across the continent. Eight German titles and three German Cups sit proudly alongside the Champions League trophy that the club memorably claimed in Munich against Juventus in 1997.
So why does the perception remain? Why are Borussia Dortmund rarely mentioned in a discussion of giants of European football?
Maybe some of it is to do with geography. Dortmund is not a big city, only the eighth largest in Germany, and while countless bars and shops in this charming municipality are adorned with the yellow and black of the football club, it lacks the powerful presence of international metropolises such as Madrid, Barcelona, Milan, Munich and the rest.
And despite the size of the stadium and fanbase, Borussia Dortmund feels like a community club rather than a European superpower. You can buy a season ticket for €190 (little more than £150) and attached to the stadium are sports facilities for locals to use. As Cristiano Ronaldo and the rest of the Real Madrid squad trained on the Westfalenstadion pitch on Wednesday evening, they were doing so just yards away from hordes of amateur runners and schoolchildren on the athletics track outside.
There's also the spectre of Munich. You didn't need to watch Bayern's brilliant demolition of Barcelona on Tuesday night to understand that Borussia Dortmund will never be the biggest club in their own country, let alone their own continent. That title is firmly in the grasp of their wealthier Bavarian cousins, who ruthlessly claimed back the German championship with six games to spare earlier this month.
And you simply had to scan the back (and front) pages when we touched down in Germany on Tuesday morning for more proof of that superiority. The sports pages were dominated by the news that Mario Gotze, one of Dortmund's brightest young players, has been lured to the Allianz Arena this summer for £32million.
Manager Jurgen Klopp did not seem angry when discussing the transfer during Tuesday's press conference, rather shrugging his shoulders at the way things are. Indeed, the enigmatic coach has also been cast admiring glances from many of Europe's top clubs, as has striker Robert Lewandowski, and it would not be surprising if all three were gone by the start of next season.
While Dortmund regularly appear in Forbes' list of the world's 20 richest football teams, it's hard for them to escape the tag of being a selling club. They are the only German football club publically traded on the stock market and financial prudence will often take priority over improving the team.
That's understandable when you survey their recent history. Poor financial management at the turn of the century forced them to sell their ground and today it bears the name of insurance company Signal Iduna. The financial problems led to inconsistency on the field and they have only reached the Champions League seven times in the 16 seasons since they won it.
Borussia Dortmund is a club of paradoxes; the huge stadium and fanbase belies their financial insecurity; their tremendous recent domestic and European success belies the inferiority complex that seems to persist about the club.
But if they overcome Real Madrid and claim a second Champions League title at Wembley next month, then maybe they can convince themselves - and everybody else - that they have a right to that seat at the top table.
Borussia Dortmund v Real Madrid is live on Sky Sports 2 HD from 7pm on Wednesday with Interactive Commentary available at www.skysports.com/championsleague