What must pilots list on a flight plan before beginning IFR flights?

Pilots are required to include all available information concerning the flight on an IFR flight plan to ensure safety and compliance with regulations. This information encompasses not just the alternate airport but also key details such as the intended route, destination airport, departure and arrival times, aircraft type, and any specific operational needs. By providing comprehensive information, pilots help air traffic control manage airspace effectively and ensure that necessary resources can be allocated in case of in-flight issues. This thoroughness also contributes to improved situational awareness for both the pilots and air traffic controllers, thus enhancing the safety of the flight.