There have been incidents where airport security screeners in some parts of the world refuse to allow tennis rackets to be cleared as cabin baggage. So whether or not an airline is fine with a tennis racket as cabin baggage for the overhead bins, there may be an issue in some places with the airport security screeners refusing to allow it. Just something to consider.

I do see people carry on tennis rackets as cabin baggage. I will ask to see what tennis pros do when traveling with their rackets.

ETA:

It seems there is a lot of room in how it goes:

https://www.epiruslondon.com/blogs/t...tennis-rackets

But I was told that it was like I thought and that the pros try to generally fly with their rackets as cabin baggage because they don’t want to risk arriving at tournaments without their usual rackets. And that it most commonly is not a problem as long as it fits the combined linear inch limits and seems likely to fit in the overhead bins.