Wishing someone a "safe flight" is a kind gesture that can be expressed in many ways depending on your relationship and the tone of the trip. The most common English phrases include "Safe travels," "Have a smooth flight," or "Text me when you land." If you want to sound a bit more classic or poetic, you could say "Godspeed," which implies a wish for success and safety on a journey. In a more casual or modern context, people often say, "Don't forget to look out the window!" or "Enjoy the sky views." If you want to use a foreign phrase, the French "Bon Voyage" is universally recognized, or the Spanish "¡Buen viaje!" is very common. For aviation enthusiasts, the phrase "Blue skies and tailwinds" is a specialized way to wish for clear weather and a fast, easy trip. Ultimately, the best way to say it is often paired with a practical wish, like "I hope the legroom is great and the landing is soft," which shows you're thinking about their specific comfort during the flight.