Recommendations for ONE travel-friendly key light for interviews

Ok so I go against the grain and typically shoot interviews with just natural light when I travel via airplane. I know, shame on me. My clients don't mind, everyone is happy. But I of course do like to bring ONE light in case it's a gloomy, rainy day. The one I have is cheap and old. Just a square LED light panel, sometimes I bounce it off a white wall just to add a little more light since it's harsh on the face. Anyways, I think I want to pay around $600 or below for a better option. Maybe a foldable mat-light? Maybe the Amaran F21? (I heard the fan-noise is a killer though). I don't need world-class. Again - my clients don't seem to care if I shoot with just utilizing window light and a bounce. I just need something small in my Pelican incase I absolutely NEED some light. Small, portable, easy to set up, maybe some kind of diffusion built in, is all I need. Thank you!