face mask (often used in Asian countries) and a small spray bottle filled with water (given in some amenity package) which I spray around my face/seat area which really helps humidify the air . There are also spray cans of Evian available to buy (but make sure you buy one that is less than 100 ml) but it is expensive and non refillable - while the small plastic bottle you can just refill as needed on the plane with bottled water