Which ingredient makes this unfit to ship by air? Says it can't be shipped to me, but not why.

Mine was shipped by air from WA to FL with no problem. It must have something to do with a policy of Amazon not to ship to your area. That's all I can think of.

Does anyone know why this increased in price?

Probably because it gained in popularity.... 'supply and demand'..... Also the availability of the 'bean' utilized to actually make the product may be in short supply due to extreme weather destroying vegetation ,worldwide. If the company has to pay more for the ingredients needed to create the product...that price gets passed on to the consumer.

What are the ingredients?

Cyclotetrasiloxane,Cyclopentasiloxane and Cyclohexasiloxane, Dimethicone, Phenyl Trimethicone, Argania Spinosa Kernel Oil Ethylhexyl Methoxycinnamate, Fragrance Parfum

When do I use the spray

You can apply it to towel dried hair and/or mist over a finished style...not to much just enough to make it shine and make it smell wonderful. I love it! I am a Hair Stylist and I use it on almost everyone...even men.