If you do not want to go from Sheremetyevo airport to Vnukovo airport by taxi, use public transport. Firstly, it is cheaper, and secondly, you can calculate travel time with minimal correction for traffic jams. The disadvantage of such a trip is a temporary restriction - the metro and express trains do not run at night.
Choose the transport that suits you best. Conventionally, the entire route can be divided into three sections: the road from Sheremetyevo to Moscow, a trip around Moscow and the road to Vnukovo airport. You can use bus or rail at different sections. The most convenient way to get around Moscow is by metro.
Method 1: Bus - metro - bus. Take bus 851 or route taxi 851E, which runs from terminals F and E of Sheremetyevo airport to the Rechnoy Vokzal metro station. You can also get to the station "Planernaya" by bus 817 or minibus 948. Then you need to go down to the metro and get to the station "Yugo-Zapadnaya". From there, buses 611 or 611с go, starting at 5.30. Vnukovo Airport is the final stop on the route. The total travel time from Sheremetyevo to Vnukovo will be 2-2.5 hours.
Method 2: Aeroexpress - metro - station "Belorusskaya") and get to the station "Kievskaya". There you will find separate ticket offices of the Kievsky railway station, where they sell tickets for the Aeroexpress train to Vnukovo. You can check the timetable for the movement of electric trains on the website aeroexpress.ru. Keep your ticket until the end of your trip as you need it to get out without hindrance. The total travel time is 1.5-2 hours.
Method 3. Combine the above modes of transport. This is convenient if you are driving towards the region in the morning hours, or vice versa, driving towards the city in the evening. For example, in the morning it is better to go from Sheremetyevo by Aeroexpress, in Moscow to use the metro services and get to Vnukovo by bus, at this time there are no traffic jams on this section of the route.