Flying in a plane takes a large amount of CO2 emissions because of how powerful that jet engine needs to be to fly the plane. If you have a choice to drive or fly, driving can have less CO2 emissions, especially if it is electric or has good gas mileage or you carpool. Train and bus is even better. But the point here is that each trip you make takes energy for the transportation to get there and back. So, if you can take fewer trips overall, that would help conserve that energy. For vacations, if you go on one big trip for two weeks instead of three trips adding up to two weeks, then you would only consume one flight for the single trip. As far as business trips, just try to only travel to meetings if really needed. Take meetings with video conferencing tools so no travel is needed.