Planting a bomb especially of that size (needing a vehicle and multiple men to move) in the ground under a paved taxiway at a major airport without anyone notic

Planting a bomb especially of that size (needing a vehicle and multiple men to move) in the ground under a paved taxiway at a major airport without anyone noticing? Not very likely. The WWII explanation is much more plausible. It happens at Schiphol too that they find them (luckily not by them exploding randomly but usually during construction efforts)