Not necessarilySoundwave only ever flew once in tape player mode (in the episode 'Masquerade', which is generally regarded as an error or lazy animation) and the only time I remember Megatron flying in gun mode was in the second lot of Transformers/GI Joe crossover comics (ahead of Generation 2) when he didn't shrink either - which was probably down to the writer being unfamiliar with the property.
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emvee cruor deo cruoris,
Fri 27 Apr 2012, 11:27,
archived)
When I say 'fly', I mean that he didn't instantly fall to the ground when turning into a gun,he normally seemed to find his way into someone's hand ;)
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drimble he'd been white, he'd been black,
Fri 27 Apr 2012, 11:30,
archived)