She could not possibly fly commercial to meet the various individuals/groups that were on her agenda. The security issue was settled, against traveling, the moment she played her poor hand (SOTU card). If she survives as majority leader without tending to business here at home, it will be because she stuck around to fight off the contenders (in her own party) and cling to power.
Not a chance she could've left the country while her leadership of the majority is at stake. She might have left when she seemed to have an advantage but after POTUS making his counter-move to her SOTU stunt she is going to find herself struggling to keep her Dems with her. Eventually she will need to make a deal with POTUS, to save her own leadership position. Very undermined,yes, if she clings to power. Damage control now, hence the accusation of POTUS leaking commercial trip even though no such trip was actually going forward. She needed a public excuse for staying.