I’m not sure what you’re asking about.
There are two passwords that can be referenced here: the MacBook Air login password, and the Activation Lock password.
The login password can be reset, and potentially the contents erased and restored from backup.
For Activation Lock, that’s intended as a theft deterrent and intentionally difficult to bypass, and you will need to recover access into that Apple Account, or have the assistance of the account holder, or present the original purchase receipt from Apple or an Apple authorized reseller to Apple to request Activation Lock removal.
And AFAIK, Internet access is required to activate a new macOS install, as well as other security-related operations.
A selection of links: