A telescoping tube for fuel transfer operations has a fixed part and a moving part, the moving part further having a dynamic sealing system which guarantees the sealing of the moving part against the fixed part, a cushioning system which absorbs the energy of the impact of the moving part against the fixed part in operations for extending and retracting the tube and protection systems against electrical discharges which ground the moving part to the fixed part, the aforementioned dynamic sealing, cushioning and protection systems all being incorporated in a single unit in the moving part of the telescoping tube. Additionally, the invention relates to an in-flight refuelling system for a tanker aeroplane, to carry out in-flight fuel transfer operations to a receiving aircraft, having a telescoping tube with the abovementioned characteristics.