Abu Hurayrah (may Allah be pleased with him) reported that the Messenger of Allah (may Allah's peace and blessings be upon him) said: "I saw Ja‘far flying in Paradise with the angels.''
The Prophet (may Allah's peace and blessings be upon him) saw in a dream his cousin Ja‘far ibn Abi Tālib flying in Paradise with the angels. Therefore, he was called Ja‘far At-Tayyār, meaning "the flying Ja‘far", and Dhu al-Janāhayn, meaning "the one with the two wings". Ja‘far was martyred in the battle of Mu'tah after both his arms were cut off, so Allah, the Almighty, replaced them with two wings with which he flies with the angels in Paradise.
Explanation in Arabic
رأى النبي صلى الله عليه وسلم في المنام ابن عمه جعفر بن أبي طالب رضي الله عنه يطير في الجنة مع الملائكة، ولذا سُمي بجعفر الطيار وبذي الجناحين، وكان جعفر قد استشهد بغزوة مؤتة بعد أن قُطعت يداه، فعوضه الله عنهما بجناحين يطير بهما في الجنة مع الملائكة.