"Island approach, India-Golf Niner-Niner checking in, VFR on top, over. Island Tower, this is India-Golf Niner-Niner, requesting vectors to the initial, over."
Here she's hailing the tower, giving her callsign IG99, indicating she's using Visual Flight Rules on top of cloud cover (she wouldn't be using VFR if she was flying on instruments of course, e.g. during a storm where seeing the runway during approach is impossible), and requesting the position and heading corresponding to the runway on the island to which the aircraft controllers are supposed to direct her.
At this point she gets nervous, goes back to put her uniform on where she discovers Dash and Violet. While she's talking to Violet's friend she hears a warning signal, goes to the cockpit and sees missiles appear from below.
"India-Golf Niner-Niner, transmitting in the blind guard — disengage, repeat, disengage! Disengage, repeat disengage! Friendlies at two-zero miles south-southwest of your position, angels 10, track east, over!"
Once again she identifies herself before continuing. Transmitting in the blind guard means she hasn't established contact with the tower, and she's hoping they can hear her. She gives her position and altitude -- angels 10 meaning 10,000 ft, and track east meaning she's flying eastward.
"Mayday! Mayday! India-Golf Niner-Niner is buddy-spiked! Abort-abort, there are children aboard, say again, there are children aboard this airplane!"
This is the desperate call for help. She correctly places mayday before her callsign, though it is supposed to be said three times. Similarly, "abort" is probably also supposed to be said three times, which she does at the end. Buddy-spiked means a friendly aircraft has missile lock.
In the extras, the director said that Holly Hunter refused to do the scene without understanding the jargon, and it shows -- she really pulls off the emotion of the scene while remaining in complete control. The whole movie is great, but this is by far my favorite scene.
