We're flying to Mumbai to help make a pedal-powered stage for an NDTV Greenathon in March. The 24 hour TV show will raise money to put solar-power in villages which have never seen light after dusk.
Flying there and back will burn approx 240,000 litres of aviation fuel and use 12,000 kWh per passenger*.
Pedalling at our sedate 50 watt rate, we would have to pedal for 240,000 hours each to generate the equivalent energy, that's about 27 years and 4 months of constant pedalling.
*Figures from the excellent Sustainable Energy Without the Hot Air by David MacKay which is available to read online for free.