A Delta Air Lines Airbus A350-900 XWB.viper-zero / Shutterstock.com Two Delta Air Lines flights from South Africa have had to make fuel stops in the past week. A mix of worsening weather conditions for aircraft and increased passenger and/or cargo count might be to blame, experts say. Both flights, operating from Johannesburg to Atlanta, were operated by Airbus A350-900 XWB planes. Two Delta Air Lines flights from South Africa to the US have had to make unscheduled stops for fuel in recent days on their way back to the US.