wg100
It's a fire retardence thing. Most of us military folk fly in clothing designed to slow/lessen the impact of a flash fire, which is a bit more likely for us in an incident. If an airliner crashes, however, there is a higher chance of complete destruction (as there are no accelerated departure means), so a flash fire would be the least of your worries.
Having learnt the civvy way myself, there is little or no heed paid to the risks of flash fires when it comes down to flying attire. The risk is entirely yours. Whilst I'm not saying you should wear a flyng suit every time you strap on your C152 (you would be right royally sneered at), gloves may just give you that extra few seconds of manual dexterity to open the escape hatch should you find yourself in a field engulfed in flames. It's a balance for you between comfort and protection, especially in the summer. A good compromise would be a thin, cotton, long-sleeved roll neck (a bit like ours, but maybe a bit less olive drab), over the polyester, short-sleeved M&S shirt.