  We report an airborne gravity survey with an absolute gravimeter based on
atom interferometry and two relative gravimeters: a classical LaCoste\&Romberg
(L\&R) and a novel iMAR strap-down Inertial Measurement Unit (IMU). We
estimated measurement errors for the quantum gravimeter ranging from 0.6 to 1.3
mGal depending on the flight conditions and the filtering used. Similar
measurement errors are obtained with iMAR strapdown gravimeter but the long
term stability is five times worse. The traditional L\&R platform gravimeter
shows larger measurement errors (3 - 4 mGal). Airborne measurements have been
compared to marine, land and altimetry derived gravity data. We obtain a good
agreement for the quantum gravimeter with standard deviations and means on
differences below or equal to 2 mGal. This study confirms the potential of
quantum technology for absolute airborne gravimetry which is particularly
interesting for mapping shallow water or mountainous areas and for linking
ground and satellite measurements with homogeneous absolute referencing.
