The short answer: yes!
The long answer will tell you my experience with this as I already managed to do it three times.
The first time I took the bouquet in the plane was without really realizing. I was too tired to think about it, yet I knew I must get home with that special bouquet. I had no problem at the security check and nobody complained at the boarding gate.
As the airline company was a high profile one, my flowers were even given “assistance” on board in order not to die 😛 [now that’s what being customer oriented means!]
The second time it worked I flew with a low cost airline and this time I was carrying an orchid, therefore a pot of flowers. I made up an entire case-flow in my mind.
I was thinking how to squeeze it in my hand luggage if they ask me to, practicing my ”please pretty please” skills or even making up a story that he had just asked me to marry him and that, surprisingly, in their culture they offer flowers (instead of a ring!) for these kind of occasions.
To my disappointment, they had NO problem at the security, NO problem at boarding, nobody asked me A-N-Y-T-H-I-N-G about the orchid. Like it wouldn’t even exist! I’m saying “disappointment” because after all the thoroughly planned scenarios, I wish I could have had some adventure to tell…
The third time I did it was yesterday. They inspect my luggage twice, but no questions about the (new) orchid. You can see “her” below enjoying the view. 😀
I must mention that my travelling experience is limited to Europe, so I’m curious to know if you ever tried this on intercontinental flights. I don’t know if this works in USA/Asia/etc., but I wouldn’t expect problems.
Conclusion: if you want to make a present to your girlfriend/mom/sister/etc. and you have no space in your luggage, consider buying a bouquet of flowers. It will be double appreciated because you brought them from literally another country 😀