The difficult choice of the right means of transport
You will certainly be aware that airplanes and cruise ships are considered to be the ultimate polluters. I would completely do without cruises anyway. But I am also rethinking air travel more and more often. The fact that flying is becoming cheaper and cheaper naturally makes it tempting to get on a plane. But especially on short journeys, the plane is not always the best choice of transportation. After all, with check-in, boarding and landing, the time saved by flying is minimal. However, the journey is more stressful. If you take the ICE instead, you can travel through to your destination without disruption and use the time productively. I also find traveling by train the most relaxing!
If you do want to travel a longer distance, consider making a road trip out of it instead of flying. With the right car, driving is also more CO2-efficient than flying. You will also see much more of the world on a road trip. You can stop here and there and discover new things.
If you can't think of an alternative to flying, then simply take a sustainable approach to flying. Instead of flying to Portugal several times to discover Lisbon first, then Porto the second time and then the Algarve, you can combine everything. Book a flight to Portugal and then travel from A to B to C by bus, train or car. This way you can discover everything in one go instead of flying there several times.
To soothe your guilty conscience from flying, you can also offset your carbon footprint by planting trees. If you don't have the space to do this, there are plenty of organizations such as atmosfair that will offset your carbon footprint for you in return for a small donation.