Pep Guardiola said Barcelona will alter their travel plans to reach the Champions League final on Saturday if obliged to do so by the volcanic ash cloud that threatens to disrupt European air travel this week.

The Barcelona coach ruled out the possibility of Uefa postponing the game against Manchester United at Wembley, insisting the club will do what the experts advise – even if that means flying on Tuesday, two days ahead of schedule. The problem, he added, will not be for the team but the fans, 12,000 of whom are scheduled to fly to London on Saturday afternoon. "It would be a terrible pity," Guardiola said, "to play in a [partly] empty stadium."

Forecasts suggest British airspace may be affected on Thursday, with flight disruption a possibility. This is not the first time that an Icelandic volcano has stood between Barcelona and a European trip. There is a dark precedent for the Catalan side, who were forced to undertake a two-day coach trip, stopping overnight in Cannes, when they travelled to Milan to face Internazionale in last season's semi-final. They were beaten 3-1 at San Siro and went out of the competition.

"We hope the volcano stays asleep for a few more days and allows our fans to get there," Guardiola said. "We will do what [the experts] tell us to do. If that means travelling on Wednesday or even tomorrow then so be it. If not, we will travel on Thursday as originally planned. If they say don't worry, we'll relax; if they say get a move on, we will. What they say we will do, we will do. We will try to plan as far ahead as possible.

"This is beyond our control and it would be very bad luck if half the stadium was empty for the final. You can go by boat. With England it's that, a plane or that tunnel between France and there. I imagine the fans will be worried, just like us. Lots and lots of people – 10,000 or 12,000 people – will travel by plane on the same day and might not be able to change those plans. Let's see what happens. Uefa will not postpone the game: the final will be played on Saturday. We play football for [the sake of] the fans and I hope [they can be there]."

Guardiola admitted playing a final in London could be to United's advantage and dismissed suggestions Sir Alex Ferguson's team lack a little fantasy this season. "Yesterday and today we watched the final from two years ago and Manchester United were much, much better than us in the first half," he said. "In the second half, we had more control but it was hard. They played better than us. They are competitive, a strong team, they could put out four or five line-ups and they would all be competitive. They are one of the best teams in the world – not just now but over the last five, 10 or 15 years.

"When you see Berbatov, Rooney, Chicharito, Nani, Scholes, Giggs, Valencia, I don't think you can say [that they lack fantasy]." Asked what most scares him about United, Guardiola replied: "Everything, absolutely everything."