Due to emergency conditions, my wife has to travel from one country to another via plane. She is pregnant and can deliver a baby at anytime. I am worried, what if she deliver's a baby in plane? Are there enough medical facilities available for baby delivery and what will be the nationality of the baby?

So it depends on which airline You are flying. It might comfort you to know that all SQ stewardesses are trained to deliver a baby but this is not the case for all airlines. However most airlines now have equipment which allows them to speak to medical centres on the ground for advice. In the case of a real emergency, they will also divert to the nearest airport which has a hospital within reach. With regards to nationality it depends on which country you are flying over. Eg flying over U.S. soil - you can apply for U.S. citizenship.

For nationality, most common law is that your baby "can" claim citizenship of the country where the airline you are flying in is registered. example, if you're Singaporean and flying in Lufthansa airline, which is a german airline, your baby can claim a Germain citizenship. But it all depends because many countries don't follow this rule. And with facilities to delivery a baby, most of the international airliners today have facilities and trained hostesses to help in delivering a baby in-flight