English: Can you stow your computer?
French: Pouvez-vous ranger votre ordinateur?
"Computer" is "ordinateur" (m) in French. "Laptop computer" is "ordinateur portatif" or "ordinateur portable", literally "portable computer."
Carry-on items, including laptops, should be properly stowed for takeoff and landing. In the context of an airplane, when you ask someone to "stow your computer/ranger votre ordinateur", it's clear that your referring to their laptop computer and that no passenger is bringing a desktop computer onto an airplane and using it inflight.
Thus, in a flight attendant's context, "can you stow your computer/pouvez-vous ranger votre ordinateur" is sufficient.
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