Frankfurt Airport is the busiest airport in Germany and the sixth busiest in Europe. Both BA and Lufthansa provide direct flights from the UK.

It's located just 7.5 miles from the city centre, which you can get to in just 13 minutes on an S-Bahn metro train from the station directly below the terminal (for example, by taking the S8 headed for Hanau Hauptbahnhof). If you're going straight to the stadium, that too takes just 14 minutes by bus (for example, by taking the number 61 from outside Terminal 1, heading for Frankfurt (Main) Südbahnhof). You can plan these local journeys and others on the RMV local transport website. 

As far as paying the fare goes, you're covered if you have a rail pass such as Interrail (valid for trains and S-Bahn) or the Deutschlandticket. Otherwise, you could look at the Frankfurt Card for free public transport and discounts at various tourist locations.

If you're planning to pick up a hire car from the airport, the better-known rental companies based there are Alamo, Avis, Budget, Enterprise, Europcar, Hertz, National, Sixt and Thrifty. You can see which offer the best prices here at Rentalcars.co.uk.