Recent studies of satellite laser and radar altimetry reveal a decline in Arctic sea-ice thickness over the last 6 years. This decline is in line with an ongoing loss of ice extent, as observed by satellite passive microwave sensors over the last three decades. While the opportunity to estimate sea-ice thickness using satellite altimetry first arose in the early 1990s, over 15 years ago, refining such estimates of ice thickness has been possible in more recent years with the availability of both Envisat radar altimetry and ICESat laser altimetry. Validation of these satellite datasets is required to estimate their accuracy and to better understand the interaction of radar pulses with the snowpack, and laser pulses with the ice–ocean environment. To this end, the Arctic Aircraft Altimeter (AAA) campaign was conducted in 2006 north of the Canadian Archipelago, to obtain spatially and temporally coincident aircraft underflights of both Envisat and ICESat using NASA’s P-3 aircraft. This campaign compared satellite altimetric measurements of sea-ice elevation with high-resolution airborne elevation measurements acquired by the Airborne Topographic Mapper (ATM). After correction for ice drift, the study revealed a cm-level correspondence between the ATM and ICESat measurements. Continuing this research and validation effort, the Canada Basin Sea Ice Thickness (CBSIT) experiment was completed in April 2009. CBSIT was conducted by NOAA and NASA as part of NASA’s Operation Ice Bridge, a gap-filling mission intended to supplement sea- and land-ice monitoring until the launch of NASA’s ICESat-2 mission. The CBSIT experiment consisted of two flights: a second 1000 km long underflight of Envisat and an overflight of the Danish GreenArc Ice Camp north of Greenland in the Lincoln Sea, where in situ field measurements of sea-ice and snow thickness were acquired. We will show the latest results from these two campaigns, paying particular attention to the validation of ICESat laser altimetry and the use of in situ snow-depth measurements for calibration of the airborne radar altimeters. We will also discuss plans for future in situ field research and aircraft studies of the Arctic which aim to provide further validation of a suite of instruments onboard both the CryoSat-2 satellite and NASA’s Operation Ice Bridge Mission.