1 round trip flight from Juneau to Seattle and 1 round trip flight across the country
Using data from http://css.umich.edu/factsheets/carbon-footprint-factsheet, CO2 generated averages 0.39 lbs / mile per person.
900 mile flight from Seattle, 1800 miles round trip = 718.2 lbs CO2
2600 mile flight from Seattle to NYC, 5200 miles round trip = 2,028 lb CO2
TOTAL CO2 = 2746.8 lb CO2
At $0.021 per pound CO2, round trip cost = $57.68 to offset