"The flight was postponed by bad weather for which I had a ticket". The sentence should read, "The flight for which I had a ticket was postponed by bad weather."
The sentence that contains a misplaced modifier is the following one: The flight was postponed by bad weather for which I had a ticket.
Explanation:
A misplaced modifier is a word, phrase, or clause that is improperly separated from the word it modifies or describes, making the sentence sound awkward. The sentence above contains a misplaced clause that modifies the wrong noun (for which I had a ticket), it seems as if the clause was modifying "weather". In facti, it looks as if the speaker had bought tickets for a bad weather. To fix the error and clarify the meaning, you should put the clause next to the noun it is supposed to modify (see 1).
1) The flight for which I had a ticket was postponed by bad weather.