By large umbrellas, I mean the non-collapsible ones that look like these :
Will there be any issue with bringing around a long, pointy object on aircraft?
It won't be an issue due to pointiness. Knitting needles are allowed too, and they're even pointier. The only possible issue would be if the overall length is deemed excessive...which is unlikely on a regular commercial flight. Worst case the crew might ask to take it from you and store it in their "closet" on board.