That's such a good question XD! Well, I'd say there is a subtle difference between "ha sido" and "ha estado" in that case. "Ha sido" implies a single action and it doesn't matter when it starts or finishes. "Ha estado" implies that the action lasted for a while. "El auto ha estado detenido....por tres horas. "El avión ha sido detenido.... por la policía" BTW; I'd say "El avión está demorado/retrasado". "El avión ha sido demorado" doesn't sound well to me.

"ha estado" it's different than "ha sido". They are different verbs. At your example, you are using those two verbs as "to be". In Spanish we use verb "ser" and verb "estar". And on "ha sido" you are using the verb "haber" too. http://www.aulahispanica.com/node/199

To be = "Ser" and "Estar" both of them are to be, but you have to learn them separately if not you are going to be all confused, not to meniton that "to be" is the most irregular verb in spanish and past, future and present continues are very very hard. We can talk about this in our next meeting if you want, we can start practicing "Ser" first :).