Great comment! After reading this, you may wonder: why didn't the armies try to bomb railroads to prevent reinforcement from being rushed to the front? It turns out, they tried very hard but the technology was just too rudimentary. The French made a bombing units of Voisins bombers but they could only carry light payload (130lbs for the Voisin 3). The Brits got the Handley in 1916, which was bigger and quite successful (this doc has a ton of details on British bombing: https://www.airuniversity.af.edu/Portals/10/AUPress/Books/B_...). If you squint hard enough, you can start seeing the emergence of patterns of WW2 warfare by the end of WW1. Fascinating.