When she was House Speaker, she was required use. As a part of the succession plan she has to use government aircraft. The question arose because she was flying with a huge entourage and her staff kept requesting large aircraft or aircraft that could make the trip in one stop. The child molester, Denny Hastert, used a small jet but he was going a short distance.
As I recall they also demanded that the aircraft be stocked with wine and other expensive "refreshments".
"by Robert Longley Updated September 04, 2017 The President of the United States and the Vice President are not the only non-military U.S. government officials who regularly fly on aircraft (Air Force One and Two) owned and operated by the U.S. government at the cost of taxpayers. The U.S. Attorney General and the Director of the Federal Bureau of Investigation (FBI) not only fly - for business and pleasure -- on aircraft owned and operated by the Department of Justice; they are required to do so by executive branch policy."
And...
"By JAKE SHERMAN 10/30/2015 05:07 PM EDT House Speaker Paul Ryan will continue John Boehner's self-imposed prohibition on using government-chartered, private jets. As second in line to the presidency, the speaker of the House is allowed use of an Air Force jet to travel around the country. When Boehner (R-Ohio) took the speakership in 2011, he vowed to not use the jet. On Friday, Ryan's office told POLITICO that he would not use the jet, either. Boehner's prohibition did not extend to overseas travel. Nancy Pelosi caught flak when, as speaker, she flew home to San Francisco on a military airplane. That prompted Boehner's decision to impose the ban."