2016 Macbook Pro 15" In Flight Power Solutions?
All of Apple's USB C chargers will charge your 15 inch MacBook Pro. To avoid the 75 watt limitation, grab one of the 61 watt chargers. 


https://www.apple.com/shop/product/MNF72LL/A/61w-usb-c-power-adapter


I use the MacBook charger (29 watt - same as iPad Pro charger) for most trips due to smaller size. I run software that drains the battery in 12 hours so I don't need the faster charging rates the 61 or 87 watt adapters provide.