Vs a piloted aircraft? The difference is there but not in the realm of 2:1. As more tech gets loaded on them I suspect they'll reach parity with manned systems. The issue isn't so much wartime cost but the fleet cost as a whole. You get X drones from your budget and they cost a lot of money to maintain (not dissimilar to manned aircraft) so you can't always just have enough to make up for time in transit.