What time did the third plane hit the pentagon?

Only one plane hit the Pentagon in the September 11th attacks. American Airlines Flight 77 hit the Pentagon at 9:37 AM EST.

There were four planes involved in the attacks, including Flight 77. American Airlines Flight 11 crashed into the World Trade Center's North Tower (1 WTC) at 8:46 AM EST. United Airlines Flight 175 crashed into the World Trade Center's South Tower (2 WTC) at 9:03 AM. The fourth flight involved was United Airlines Flight 93 which crashed into a field near Shanksville, Pennsylvania at 10:03 AM EST.