Asking for money.. is that rude?

Is it rude to ask someone to pay for your plane ticket to visit? We had already agreed she would drive but last minute she started asking my husband to pay for a plane ticket. She wants to be there the second I go into labor so she wants to hop on the next flight but expects my husband to pay for it. The thing is I want us to pay for it anyways but it just kind of irritates me she asked us to pay for it instead of letting us offer. She borrows money from all of her sons and has even from me so it’s not just a one time thing. I’d prefer she didn’t come down at all or atleast in a few weeks so I can adjust to being a new mom but my husband INSISTS and so does she that she HAS to be there the second I go into labor. And my thing is you’ve know you wanted to come down for MONTHS why couldn’t you have saved the 300 max it would be for a last minute round trip instead of asking us last minute to pay it? idk I just know my family would never loan money or ask for money unless it was an emergency so it just irritates me that she is so quick to borrow money, and that my husband feels like he’s obligated to do it. And I know all her financial burdens will fall on us when she’s visiting... maybe I’m just hormonal