Journal papers are more formal and longer pieces of writing that are subject to strict publication rules, while conference papers are typically shorter and intended for presentation at conferences with a specific audience in mind.
In addition to what Ajit Singh wrote: A publication in the proceedings of a conference (i.e. in a book), after a presentation was made at that conference, is often called a conference paper. See also: https://www.researchgate.net/post/How_to_start_writing_scintific_articles_Are_there_any_differences_between_preperation_of_conference_papers_and_journal_articles
A journal article: a more complete presentation of topic, a greater percentage of new material, a real novelty relative to other published works. But it could be no difference of text quality between a journal article and a conference paper. The main criteria is formal: is it a journal or is it a book of proceedings?
AIAA journal is a journal. And papers here are journal articles. Peer-reviewed.
AIAA proceedings contain only conference papers. They are not peer-reviewed.
Intermediate option - Journal of Physics: Conference Series - it is a book series. It contains peer-reviewed articles / peer-reviewed conference papers. Depending on the rules of the country or the competition for a grant, it may be counted as a journal article or as a conference proceedings.
A prestigious journal: a couple of weeks for being rejected and almost a year for being published. A prestigious conference: a couple of months for being rejected and only few moths later for being published. :D