In the early on 1900s , the fastest agency to deliver ship service was past times runway , only at that topographic point was a motorcar that could move faster than trains , together with that was , of shape , the airplane. So inward the 1920s , the States Post Office began experimenting with this novel flight motorcar that was latterly used with smashing success inward the First World War. There was , nevertheless , i major problem: dissimilar trains that could operate all nighttime together with on all weather condition , airplanes could exclusively wing during the twenty-four hr current together with exclusively when the weather condition permits.
Flying was soundless a risky business. Bad weather condition , pathetic instruments , erstwhile aircrafts together with maintenance errors were alongside the many threats pilots had to bargain with when flight a mission. This was besides the fourth dimension when at that topographic point were no GPS , radar or radio guidance. Pilots had to navigate their agency across the dry reason past times picking out visible landmarks upwardly from the air. This made flight at nighttime impossible. Even during the twenty-four hr current , non all regions were recognizable , specially when flight higher upwardly vast stretches of empty , repetitive deserts.
Smithsonian / epod.usra.edu / Gizmodo / Sometimes Interesting