Didn't fly it, but I reckon the strangest thing I've seen was a fully operational Main line Diesel locomotive for Irish Rail that was shipped across the Atlantic on on of the Russian heavy lifters (an AN124 I think).
It took quite some work to get it out of the hold and on to the transporter that took it through Dublin to the maintenance base.
As to why it was flown over rather than coming by ship, as the rest of the order did, we never found out the reason for that.