San Francisco: Google is offering free in-flight Wi-Fi access to an estimated 15 million passengers this holiday season, the company announced on Monday. The gesture by the web-search giant will be offered on all internal US flights operated by Delta, Virgin America and Air-Tran. The three carriers recently outfitted their fleets with airborne Wi-Fi capabilities offered by the company Gogo Inflight Wi-Fi, which usually charges between $11 and $13 for 24 hours of airborne Wi-Fi access. Last year Google sponsored free Wi-Fi in 50 US airports. This year the gift will be sponsored by the company's Chrome browser and will be available on all AirTran, Delta and Virgin America flights from Nov 20 through Jan 2, 2011.