Defending champion Barcelona has an extra hurdle to overcome ahead of its Champions League semifinal away to Inter Milan. The Catalan side was forced to use coaches for the 725-kilometer (450-mile) trip to Milan after flights were grounded following the cloud of volcanic ash from Iceland that has spread across European skies in recent days. Inter and Barcelona met twice this season in the group stage. The teams drew 0-0 at San Siro and the Spaniards won 2-0 at Camp Nou. Inter is going for a treble, but has lost the leadership of the Serie A to AS Roma with four matches remaining. In its most recent match Maicon and Samuel Eto'o scored in a 2-0 win over Juventus. 