Lighters 101
Use a butane lighter for a cigar, ideally a torch with a steady flame you can hold on the foot while you turn the cigar. Matches work too, including a slow-burning cigar match. A strip of Spanish cedar from a cigar box, lit and held to the foot, is another traditional way to toast it.

Do not light a cigar with a fluid lighter. The fuel smell gets into the smoke.
Refilling a butane lighter
Use a clean, filtered butane. A dirty refill clogs the valve and the lighter starts to sputter. Let the lighter cool before you fill it, and turn the flame down.
Bleed the tank first. Hold the lighter away from your face and press the fill valve with the plastic tip from the can, not a screwdriver. A metal tool scars the valve. You will hear the old gas leave. Then turn the lighter upside down, seat the can’s nozzle straight onto the valve, and fill in short bursts until it will not take more. Wait a few minutes before you light it, then set the flame back to the size you want.
If the lighter will not light after a refill, there is often air in the tank. Bleed it and fill again.
Torch and soft flame
A torch is a focused blue flame. It lights a large foot quickly, and it stays lit in a light breeze better than a match does. Hold it just off the foot. Touching the cigar with the jet scorches a hole instead of lighting the leaf evenly.
A soft flame is the wider yellow flame on some butane lighters. It is slower and easier to overdo, so keep the cigar moving. It is a reasonable choice for a small cigar. Matches are a soft flame too. Let the sulfur burn off a wooden match before it meets the foot.
Looking after it
What you can take on a plane is a different question from what lights a cigar well. A torch and a can of butane are the pieces people have taken away. That is on Traveling with cigars. Matches are the simple light once you have landed.
A lighter that sputters after a clean refill often has a clogged jet. A short blast of butane through the jet, with the flame adjuster open and no spark, clears a mild clog. Do not take the lighter apart if you are not sure how it goes back together. Store it away from heat, and do not leave it in a closed car. Butane expands, and a hot tank can vent on its own.