"I get on an airplane at the airport."
Helpful. Thanks for the explanation. :) Now I just have to memorize the differences and not get them mixed up... Guess the only way to do that it rote. Or...maybe... Hm. "De" is the first sound in "death" which is permanent, so it's used for permanent fixtures like a school or a city. Kind of morbid, but I think it may work? Like, "de" is for "you can point to it on a map and it's unlikely to have changed location." "Ni" is for things that change in time/location, like the hour or a car. Do I understand that right?
This is neither accurate nor helpful. で is used for indicating where an action took place.
空港で飛行機に乗ります 空港で昼ごはんを食べます 空港でりんごを買います
Meaning "I board a plane / I eat lunch / I buy an apple at the airport"
に is used to indicate in a direction in this context, に乗ります is like I am getting ON the plane. But it can also be used to indicate that something exists somewhere. That's when people get it confused with で
空港に飛行機があります 空港に人がいます 空港にジョンスミスがいます
"There is an airplane / a person / John Smith at the airport"
Basically for the verb のります you always use the particle に to indicate the vehicle you're boarding or in which you already are, and in japanese sentences in general you want to avoid using the same particle even if it acts in different ways, therefore here you use で to indicate the place where the action is taking place.
I reversed the position of ひこうきに and くうこうで and DL marked this wrong. The correct particles were connected to the appropriate nouns and the verb was correct and in the correct position. Basically I wrote "At the airport, I get on an airplane." I thought that was all right to reposition nouns and their particles. Is this an error? Please advise. Arigato in advance.