Johannesburg - South African Airways (SAA) has scheduled extra flights on Wednesday to reduce the backlog created by restrictions at Heathrow airport caused by heavy snow and ice.SAA spokesperson Fani Zulu said: "We are now back to the normal schedule."On Tuesday Heathrow gave the go-ahead to operate two special flights out of South Africa in the morning, which arrived in the afternoon.Three flights arrived out of Heathrow to South Africa.SAA had a surprisingly low passenger turnout with 26 on a flight from Cape Town and 126 on a flight from Johannesburg, but the airline needed to get the planes to London to bring people to South Africa.Zulu said SAA put word out on Tuesday night about the extra flights, and thought the low turnout was a combination of cancellations and people not receiving the message in time.A notice on Heathrow airport's website said it was operating a reduced flight schedule on Wednesday and posted 14 pages of "reduced" departures and arrivals.The authority warned that more inclement weather was expected and that there could be further delays.Global travellers have been stranded since the weekend, when heavy snowfall and ice saw the world's busiest runways temporarily closed."If your flight is on the list, please contact your airline to confirm before leaving for the airport. More cold weather is forecast and there may be further delays and cancellations."The statement on the website www.heathrowairport.com continued: "We are truly sorry for the disruption the weather is causing to our passengers. We are doing everything we can to get you on your journey."The Telegraph online reported that the Eurostar service between London and Paris was subject to long delays.British Prime Minister Bruce Cameron was quoted as saying he was frustrated by the long delays while at least one airline, BMI, has complained that Heathrow does not have enough de-icers for the runways.British airport authority BAA chief executive Colin Matthews has warned that it will take time before normal service is resumed, and pledged a full investigation into how the situation could have been managed better.