Euston Station sees its heaviest traffic on weekday mornings and early evenings, when the main approach roads are shared between commuters and airport travellers. If your journey falls in one of those windows, building in some extra time is sensible; outside them, and at weekends, the roads are typically quieter. Either way, the route is planned around the traffic on the day, not around a fixed schedule that ignores it.
On the day, your driver confirms the pickup point in advance so there is no last-minute searching, and for airport legs the flight is tracked so the car is ready whether you land early or late. Allow the usual airport routine either side of the drive itself: security and check-in on the way out, and passport control or baggage reclaim on the way in, both of which our free waiting allowance already covers.
Telling us your group size and luggage at booking, rather than leaving it to the day, means the right vehicle is waiting: a saloon for up to four people and two large cases, or an estate, MPV or 8-seater for more bags, buggies or equipment. Journeys like this get busier in school holidays and summer, so booking ahead is the simplest way to secure the size of car you need.