Re: Preposition ommission
Many teachers (and editors) are fussy about parallel structure, and in this case I'm one of them.
Verbs can share a preposition if the same preposition is appropriate for each verb.
The kids like to splash and play in the pool. It is not necessary, and more than a little awkward to say splash in and play in.
Your example is quite different. One cannot take off on a roof, one must take off from and land on something. That is just how those prepositions work with those verb phrases; I don't think there is a rule other than what I said above.