Most Famous Senator to the General Public?

[Mr. Morden]

Besides Bernie Sanders?  Maybe Mitch McConnell.

I'd say Cruz and McCain are far more well known than McConnell.  This is by no means a perfect measure, but looking at Gallup's favorability tracker:

http://www.gallup.com/poll/1618/favorability-people-news.aspx

in their August 2016 polling, only 8% of respondents had "never heard of" or had "no opinion of" Sanders, compared to 13% for Cruz.  McCain hasn't been polled since August 2015, but his number at that time was 11%.  McConnell was last polled in Oct. 2015, and his number was 40% having no opinion or never having heard of him.

My guess is that McCain would have been the most famous Senator as of ~18 months ago, but the 2016 election cycle introduced Sanders, Cruz, Rubio, Kaine, etc., with Sanders presumably now the most famous.

[Mr. Morden]

Amy Klobuchar recently described something that happened to her during a flight.  She and Al Franken were flying to Minnesota from D.C. and the pilot announced he was happy to have Senator Al Franken and his wife on the plane.  Klobuchar explained that she's also a Senator and the pilot then said "isn't that great, husband and wife are both U.S. Senators"

Where did you hear this?

She said it when she spoke to the new members of congress.

She's told that story many times before.  E.g., she told it to all the state delegations she spoke to at last year's DNC:

http://www.startribune.com/at-the-convention-klobuchar-and-franken-are-both-in-demand/388491891/

(You know, when she was kicking off her 2020 presidential campaign.  )