Very safe.The only reason air crashes hit the headlines is because of the number of people who die at one time.More people die on the British roads every year than do in air crashes.If your numbers up your doomed whatever you do.
Mile for mile, it is the safest form of travel, but that doesn't help at all if you are scared of flying. If your fear is fairly mild, see your GP for a mild tranquilisr to relax you while you travel. If it is more serious, you can be referred for therapy - contact your local airport who will probably refer you - but it may cost some money.
They do courses for about �200 at most larger airports which also include a short flight at the end when hopefully your fear is conquered. I am petrified of flying but still do it every year. I have panic attacks on the plane and hyperventilate which is very embarrasing. I don't fear the crashing as such because more people are killed by donkeys in England every year than are killed in air accidents (true fact!) but I don't like the loss of control or the compact space in an aircraft. I think it helps if you can target what you are most afraid of to try to tackle that first. I found that talking to the pilot before people were allowed on the plane helped to steady my nerves a little. There are also some very good web sites which tell you everything you need to know about flying. I think the one I went on was www.fearofflying.com. Basically a pilot answers any questions you may have as honestly and as simply as he can.
*sounds very loud horn* I wondered how long it would take for someone to come up with the "donkey" statistic. It is, of course, totally made up. It may conceivably be true (the incidence of both causes is death is very low) but there are no collated statistics on donkey trampling, so no-one knows for sure. Anyway, as to the central question of whether air travel is safe, yes it is. If it wasn't, who'd be a pilot?
"Just remember to get a seat at the back" wrote sddsddean. Unfortunately there is no evidence to suggest that these seats are safer or should I say less safe?