@WestCoasterBC The 2013 Air doesn't have an ethernet jack unless using a thunderbolt to ethernet adapter which Apple sold separately for like $70.
@Mgwhis If your phone and other devices can connect, the issue will typically be with the MacBook. Resetting the gateway is usually a last resort and if only one device is impacted, it rarely fixes this issue. Slowly loading pages won't be DNS either. In the past the 2013 Airs were known for having wifi issues to the extent that Apple had to release a specific update for just that model.
A few questions: