“Rodger” was the original meaning for the letter “R” in the phonetic alphabet. First making its appearance around 1938 it was used by the military in place of the “received.” It meant that the transmission sent, whether by radio or Morse code, had been received by whom it was sent to. The military later replaced it in 1954 with the current phonetic alphabet.
Contrary to popular belief it did not mean that the message would be complied with. In today’s world the military still acknowledge the receipt of a command or orders by the term Roger by replying, "Roger, returning to base" or however relevant. In the phonetic alphabet today the term “Roger” has been replaced by the term “Romeo” when used for meaning of the letter “R.” The misconception of Roger standing for an acknowledgement and follow through of an order has been the cause of numerous accidents in aviation. In Geneva, Switcher land flights DLH3703 an ATR42-500 and KLM1931 a Boeing 737-300 crashed into each other due to a misuse of the word Rodger causing KLM1931 to hold on the runway and DLH3703 to crash into it.
Today the term Roger is still used by pilots and ATC alike to lessen actual time on the radio but it is important to note the difference in meaning between Rodger and Wilco. Wilco means that the receiver of the transmission will comply with the order. This is why the term “Roger, Wilco” is commonly heard in the military. “Roger, Wilco” formally means, “I received the transmission and will comply with the order.”