I made a few custom items with Attribute Modifiers, but it appears they do not show up.
Command:
/give @p minecraft:elytra 1 0 {AttributeModifiers:[{AttributeName:"generic.movementSpeed",Name:"generic.movementSpeed",Amount:0.2,Operation:0,UUIDLeast:0,UUIDMost:0,Slot:"torso"},{AttributeName:"generic.armor",Name:"generic.armor",Amount:10,Operation:0,UUIDLeast:0,UUIDMost:0,Slot:"torso"},{AttributeName:"generic.attackSpeed",Name:"generic.attackSpeed",Amount:0.6,Operation:0,UUIDLeast:0,UUIDMost:0,Slot:"torso"}],display:{Name:"Flight Wings",Lore:[When Equipped, You Can Fly Infinitely!]},ench:[{id:0,lvl:5},{id:4,lvl:3},{id:7,lvl:3},{id:34,lvl:10}]}
Invalid : The Slot value "torso" has been replaced by "chest" (see MC-88569). Then, your UUIDMost and UUIDLeast must not be 0, and they must be different, (see comment on MC-16466)
Here is a fixed command :