fly.lua

local modules = peripheral.wrap "back"

os.loadAPI "metaowner.lua"
metaowner.upgrade(modules)

while true do
    local meta = modules.getMetaOwner()

    if meta.motionY < -0.3 then
        modules.launch(0, 270, math.min(4, math.abs(meta.motionY)))
    end

    if meta.isSneaking then
        modules.launch(meta.yaw, meta.pitch, 3)
    end
end