Event organisers from around the world of sport have been forced to alter their plans because of the volcanic ash cloud that has grounded planes around Europe.
Restrictions on UK airspace are now easing but it could be several days before the backlog of flights is cleared.
FOOTBALL
French side Lyon have travelled by coach Germany to face to Bayern Munich for Wednesday's first leg of their Champions League semi-final.
Liverpool have finally arrived in Madrid after a 24-hour trip by coach, train and plane for Thursday's Europa League semi-final first leg match against Atletico.
The team travelled by coach and rail to Paris on Tuesday, took a train to Bordeaux from Paris on Wednesday and then flew to the Spanish city of Madrid.
Fulham, meanwhile, are making the 570-mile road journey to Hamburg in Germany for the other semi-final.
Both Liverpool and Fulham are hoping to be able to fly back on Friday in order to fulfil Premier League fixtures at Burnley and Everton respectively on Sunday.
Tuesday's Uefa Champions League semi-final first leg between Inter Milan and Barcelona went ahead after the Spanish team travelled to Italy by road.
ButCeltic cancelled their planned friendly against AZ Alkmaar on Wednesday night. "The club is hoping to rearrange the fixture against the Dutch side for the near future," said a Celtic statement.
Premier League referee Steve Bennett, stranded in Romania after attending a coaching seminar, hopes to be back to officiate this weekend.
Teams are anxious to get their cars back to factories but despite the delay, Formula 1 boss Bernie Ecclestone has said he is confident the Spanish Grand Prix, the first European race of the season, will go ahead as planned on Sunday 9 May.
CRICKET
England will stick to their original intentions to fly from Gatwick to the Caribbean on Sunday.
Widnes Vikings' Challenge Cup tie against Lezignan has been rearranged for Thursday after the French side's flight to the UK for Saturday's original meeting was cancelled.
Lezignan have already set off from the south of France on a coach trip to the Stobart Stadium.
However, the Championship match on Thursday between Featherstone and Toulouse has been postponed as the French side only made it home on Monday after Saturday's Challenge Cup defeat at St Helens.
Catalans Dragons' next Super League fixture is against Warrington on Sunday.
BOXING
Carl Froch's defence of his WBC super-middleweight title against Denmark's Mikkel Kessler in Herning will be unaffected by the travel disruption - the Nottingham fighter flew into Denmark by private jet on Tuesday afternoon.
Rendall Munroe's WBC super-bantamweight eliminator against Victor Terrazas is also set to go ahead in Coventry on Friday, with the Mexican making a marathon journey to England by plane, car and train.
GOLF
The Moroccan Golf Classic, due to start at the Pullman Magazan course in El Jadida on Wednesday, has also been postponed.
But the Ballantine's Championship in South Korea on the full PGA European Tour is unlikely to be affected, with the majority of players already in Asia after the Volvo China Open.
Organisers are monitoring the air pollution levels in London and say analysis of the dust material indicates it does not contain material that is seriously harmful to health.
EVENTING
Oliver Townend has arrived in Kentucky after a marathon journey and will bid to land the Rolex Grand Slam and the £230,000 reward on offer.
Having won at both Badminton and Burghley, the Yorkshireman is chasing the final leg of the Slam - and the lucrative prize - in Lexington.
His trek began in Ellesmere, Shropshire and has taken in Crewe, London and Paris, from where he caught a taxi to Madrid - a 14-hour journey costing around £1,600 - and then a plane to Miami and an internal flight.
The postponement means the Spanish MotoGP in Jerez, Spain on 9 May is now next up in the calendar.
HORSE RACING
Officials at Punchestown in Ireland are not expecting the volcanic ash cloud crisis to affect the British raiding party at their five-day meeting, which started on Tuesday.
Seven British-trained contenders ran at the picturesque Kildare track on the opening day.
Somerset-based champion trainer Paul Nicholls sent over Twist Magic and Denman by ferry.
CYCLING
Team Sky's Bradley Wiggins was among those forced to miss the Amstel Gold race, the first of the Ardennes Classics, in the Netherlands on Sunday.
Carlos Sastre, Alejandro Valverde and Luis Leon Sanchez were also missing as Belgian Philippe Gilbert took victory.
GYMNASTICS
The start of the European Gymnastic Championships in Birmingham has been delayed by a day, with the qualifying round set to begin on Friday.
'Remarkable' gymnasts overcome ash cloud
Organisers have sent buses to Paris, Brussels, Amsterdam and Bremen to pick up some of those taking part.
Russia, Belarus and Ukraine have pulled out, while Portugal had earlier announced their intention to withdraw but are now set to arrive on Wednesday. Other teams arriving late include Hungary, Greece, Latvia and Bulgaria.
Britain's trampolining, tumbling and DMT gymnasts, meanwhile, have embarked on a mammoth 40-hour-plus coach trip to take part in their European Championships in the Bulgarian Black Sea port of Varna.
JUDO
Great Britain's judo team will make a 900-mile road trip to compete in the Senior European Championships in Vienna, which run from Thursday to Sunday.
Kelly Edwards, Colin Oates and James Millarwill are all in action on the opening day of the tournament.
The squad's Russian, Bulgarian, Lithuanian and Slovenian counterparts were all preparing for the event at the British Judo Performance Institute in Dartford, Kent, and they, too, have decided to make the arduous journey - the Russians by train and the others on buses.
ICE HOCKEY
Great Britain's opening match against Croatia at the Ice Hockey World Championships on Saturday was delayed after the team had to swap a flight for a 26-hour bus and train journey to Slovenia.
Despite not arriving Slovenia until two hours before the game, GB showed no signs of travel fatigue as they coasted to a 4-1 win.
LONDON 2012
International Olympic Committee chiefs have been forced to carry out their review of London 2012's preparations via telephone this week.
IOC co-ordination commission chairman Denis Oswald and Olympic Games director Gilbert Felli had been planning to fly to London for the review.
DIVING
The final leg of the Diving World Series, due to be staged in Sheffield this week, was rearranged to take place in Veracruz, Mexico, following the conclusion of the second leg there on Saturday.
SPEEDWAY
Belle Vue Aces riders Hans Andersen, Peter Karlsson and Patrick Hougaard are stuck in Scandinavia ahead of the Elite League fixture against Ipswich, although German signing, Tobias Kroner, has managed to get to England and will make his debut.
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