Why does the DTV application ask for a flight number before my stay duration in Thailand is confirmed?

When applying for the Thailand DTV (Digital Tourist Visa), you are required to provide a flight number, despite some concerns about booking a flight before knowing your stay duration. This requirement exists because many Thai embassies and consulates need to verify your intended travel details during the application process. While it is not mandatory to book a flight at this stage, applicants have reported success by entering a random or proposed flight number, as the system does not always seek additional proof of a booked flight. However, it is recommended to be cautious and consider booking a refundable flight ticket just in case it is needed later.