A couple of corrections:
1. According to IPCC, aviation is responsible for 2-3% of total ahthropognic emissions of carbon dioxide (not 15%)
2. Transportation across all classes is responsible for 15% of anthropogenic CO2
3. If we take radiative forcing, the contribution from aviation is estimated at 3.5% (effects of contrails, other greenhouse gases, etc.)
4. Isn't the British Government contribution to the A380 (at least in theory) a commercial loan, repayable on royalties. Surely therefore this should not be considered here?
DrDave