They were saying their ears FELT like they were in an airplane, not that they actually were in one. The clogged ears are also a symptom of whatever bug they have.
For one, most people have trouble with their ears when in an airplane. The pressure difference has an effect on anybody. For another, if you have a sore throat and swollen lymph nodes, you MUST try to see a doctor. Try to keep your mind open, and don't try to diagnose yourself. Only a doctor can diagnose and treat an illness. Lots of juice, clear liquids, and try to avoid caffeine and sugary things. Vitamin C is important. But try to see a doctor, rather than ask the internet to diagnose you. The internet isn't nearly as reliable as a real doctor.
Did they give you antibiotics? You could have an infection in your lymph node.