There aren't any exact numbers yet, but Starship will burn about 5000 metric tons of propellant in a single launch. Assuming a stoichiometric ratio of CH4 to O2, that'll emit about 2600 metric tons of CO2 (the rest is water). According to the ICAO emissions calculator, a roundtrip by plane between LA and London emits about 0.9 metric tons of CO2 per passenger. Thus, a Starship launch generates the same emissions as 2900 passengers making that trip.

At the $400 price I get for that trip on Google Flights, those 2900 passengers generate about $1.2 million in revenue for the airline. A single Starship launch will generate $100 million in revenue for SpaceX.