All my latest planes have been PLA+. It is a little more durable than PLA. Plenty durable for flying and landing…but if you crash, mid-air collide, or land very hard you are going to break something. I mainly use it for the increased heat resistance. In that respect it is better than regular PLA but in a hot car it will still warp. I had 2 planes in the back of my car that I left in just a tad too long. One was PLA the other PLA+. Both planes warped and were unflyable, but the PLA+ plane did not warp as badly as the PLA plane. People are trying different materials now to find something better but most have proven too difficult to print with. ABS warps too much unless you use a heated enclosure. ABS+ I haven’t been able to get good enough layer adhesion yet to make it work properly. ASA looks like it has some promise but not enough testing has been done with it yet.
I use eSUN Pla Plus for nearly everything, especially 3D printed airplanes. The exception is some canopies which I print using a “clear” regular PLA because eSun doesn’t make a clear filament in Pla Plus. In normal handling I can tell the difference both in strength and toughness (I’m talking about toughness in the engineering sense).
I cartwheeled my Sturmovik on landing twice with zero damage, which is impressive considering it’s a large, heavy model.
Of course “durable” is in the eye of the beholder. Crashes with plastic airplanes are about the same as models using other construction methods. The difference is that repairing a major crash with a 3D printed airplane is more often than not impossible, especially compared with foam airplanes. For example, I don’t even try to cut out a broken wing panel to replace just the broken part. If anyone has figured out how to do this properly and wind up with a structurally sound component, let me know.