I used to have ubuntu 16.04 lts . Now I have 18.04 lts . In 16.04 when I disabled wifi , that option was preserved after shutdown and boot . Now in 18.04 lts if I disable wifi the option is not preserved . Hence the problem is not due to my G505s lenovo laptop . I know that airplane mode disables more than just wifi and I prefer that mode for personal reasons . I have searched in the internet and have not find anything helpful . I would like to know how to preserve airplane mode in 18.04 lts .
Paste the following lines or type them into the file:
Save and confirm the filename with ctrl-x, y.
Details can be found here link