First of all you can enchant the elytra with Unbreaking in survival.

An enlytra enchanted with Unbreaking acts strange as instead of decreasing the durability per time (like it is with an unenchanted one: one less durability per second), it rather happens randomly sometimes not decreasing the durability for about 20 seconds, then for 4 seconds decreasing it by 1 per second. There seems to be no pattern for this (at least I cannot see one).