I think that you are referring to Bereishit Rabbah 21:5.
There, Rav Papus understands the verse to be suggesting that people sought to become like one of the ministering angels. Rabbi Akiva disagrees, and interprets the verse as indicating that they chose the path of death instead of the path of life. Rabbi Yehuda bar Simon understands it to mean that they sought to become like God himself, while the other rabbis understand it to imply that they sought to become like Gabriel. Finally, Reish Laqish suggests that before this point they had been like Jonah, while Rabbi Berekhiah believes that they had been like Elijah.
A number of things about the passage are difficult to interpret, not least among which is how Reish Laqish connects the text to Jonah in the first place. The Maharzav (Rabbi Ze'ev Wolf Einhorn) and the Rashash (Rabbi Shmuel Strashun) connect the word אחד in the verse (כאחד ממנו) with the same word in 2 Kings 9:1, which both Rashi and Radaq connect with Jonah (based on Seder Olam Rabbah §18).
In any case, the language used by Reish Laqish is as follows:
(The notion that Jonah lost all honour is explained by the Maharzav in situ, in reference to a passage at the beginning of the Mekhilta.)