: If the software is already installed, you can often find it by going to Help > About or viewing the RealFlight Launcher Activation & Usage Where to find the serial number of an RF-9
Regular additions of E-flite and Blade aircraft.
: On some versions, it is located on a paper sticker on the back of the InterLink transmitter (often on the battery cover). Digital Purchase
Your key is tied to your Steam account forever.
If the software is already installed, you can often find the serial number in the launcher or by navigating to Help > About within the application. Upgrade to RealFlight 9.5S (Steam Version)
On some versions, it is printed on a sticker on the back of the InterLink DX controller.