The Spanish champions made the 350-km journey after a strike by Spanish air traffic controllers dashed their plans to fly direct to Pamplona on the morning of the game.
Barca put out a statement early in the afternoon to say they had an agreement to postpone the match to Sunday, but this was soon contradicted by the RFEF and Osasuna, who insisted the match went ahead as scheduled.
Barca arrived at the Reyno de Navarra just before the start time of 1900 GMT, and after a 50-minute delay they went on to win 3-0 with two goals from Lionel Messi to stay top of the standings.
"The federation told us that if the plane didn't leave the game would be postponed," Guardiola told reporters after the match.
"The country has suffered a huge problem. We were just some more amidst 400,000 stranded travellers. We had considered catching a train but AENA (Spain's airport authority) told us we might be able to fly.
"We never travel the same day by coach. To play against Osasuna who had not lost at home in 12 matches we wanted to be at our best.
MILAN TRIP
"We don't mind travelling, last year we went 14 hours by coach to play in the Champions League (a semi-final first leg against Inter Milan due to a volcanic ash cloud), because UEFA said they wouldn't postpone.
"Now we know how this country works and when the federation is put under pressure, we have travelled because we preferred to come than to lose three points."
The RFEF revealed how they had played their part in the confusion when secretary general Jorge Perez spoke to radio station RAC1, earlier in the day.
"It was an initiative by the federation to postpone the game," he said. "We wanted the game to be played this weekend, but Osasuna were never in agreement."
Barcelona put a detailed statement on their website listing what had happened throughout the day.
"At 1330, the federation confirmed the postponement to our president and at 1500 for unknown reasons they changed their opinion and told us the match would go ahead as planned," Barca vice president Jordi Cardoner told Spanish media.
"Obviously there has been a misunderstanding."
Saturday's other two matches were unaffected. Valencia travelled by coach to the Spanish capital on Friday afternoon to play Real Madrid on Saturday, in a match they lost 2-0.
Atletico Madrid went in the opposite direction, also by coach, and lost 2-0 at Valencia-based Levante on Saturday.
