Does a Kenya eTA guarantee permission to travel?
No. A Kenya eTA is the government's license to travel to the Republic of Kenya, and a valid eTA must be presented throughout the check-in and boarding procedure. Your carrier may still refuse to board you if you do not show other needed papers such as your passport and/or boarding permit.
Additionally, you may be questioned at the point of departure or arrival. This may result in you being refused access to the mode of transportation.
You should apply for the Kenya ETA at least seven days before departing. Although most applications are handled within 72 hours, it is best to leave time for any potential delays.