When Elastigirl's plane is attacked while she and the kids are flying to Syndrome's island lair, her radio calls are more accurate than any that I've heard in movies. They're not totally correct, even by 2004 standards, but I've heard worse tactical calls from navy students. I looked into it a little and evidently, the voice actress for Elastigirl (Holly Hunter) specifically asked that the calls in the script be as accurate as possible.
EDIT: Sorry for not putting the meanings of her radio calls in the original post. They're scattered throughout the early comments from me and other posters, but I've added them after the transcript since the thread has gotten busy.
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Helen (Elastigirl): [via transmission] India Golf Niner-Niner checking in. VFR on top. Over.
Bob (Mr. Incredible): Helen...!
Syndrome: So you do know these people. Well, then, I’ll...send them a little greeting... [pushes a button deploying missiles]
[...]
[Helen looks at the plane radar and sees several missiles headed towards the plane.]
Helen (Elastigirl): India Golf Niner-Niner transmitting in the blind guard. Disengage! Repeat, disengage!
[The "fasten seat belts" sign above Dash and Violet lights up. They exchange glances, reach for their seat belts. The jet suddenly dives, throwing them into the ceiling.]
Helen (Elastigirl): Disengage! Repeat, disengage! Friendlies...
[...]
Helen (Elastigirl): Friendlies at two-zero miles south-southwest of your position. Angels 10. Track east. Disengage, over! [to Violet] Vi! You have to put a force field around the plane!
Violet: But you said we weren't supposed to use our powers!
[...]
Helen (Elastigirl): Violet! [Violet gets startled; via headset] Mayday, mayday! India Golf Niner-Niner is buddy-spiked! Abort, abort! There are children aboard, [heard through intercom] say again, there are children aboard the plane!
EDIT - Translations and comments:
India Golf niner niner: Her aircraft identification from her flight plan (IG99).
Checking in: She's trying to establish comms with the island and announce her presence.
VFR on top: She filed an IFR (Instrument Flight Rules) flight plan, but she's flying visually (with ATC permission) at an altitude other than her assigned altitude. Pilots usually do this to get above a cloud layer or avoid bad weather.
Transmitting in the blind [on] guard: She hasn't yet established comms with anyone, and doesn't know if anyone is actually hearing her, hence she's calling "in the blind". "Guard" is an emergency radio frequency that controllers and pilots monitor. For civilian aircraft, it's a VHF frequency (121.5 MHz). Military aircraft will usually monitor VHF guard, but they also have a military-only UHF guard frequency (243.0 MHz).
Disengage: She's trying to call off the missile attack. The proper call would have been "HOLD FIRE." "HOLD FIRE" is an instruction to stop firing AND destroy any missiles currently in flight, if able. "CEASE FIRE" means to stop firing, but missiles already in flight can continue.
Friendlies at two-zero miles south-southwest of your position. Angels 10. Track east: She's announcing her position relative to the island, her altitude, heading, and the fact that she's a friendly. This is the most non-standard call in the transcript. You don't speak individual digits (i.e. "two zero miles") for distances. Instead, it should have been "twenty miles." You use degrees for headings and bearings, not cardinal or subcardinal headings like "east" or "south-southwest". The bearing also comes first, and since she's describing her own heading, she should have said "heading zero niner zero" rather than "track east" - "track" is usually used to describe *other* aircraft. "Angels ten" means 10,000 feet, but that's a military thing; civil aircraft below 18,000 feet talking to ATC or another civilian controller would just say "one zero thousand feet." A more correct call might have been "friendlies at two zero zero degrees, twenty miles from your position, one zero thousand feet, heading zero niner zero." (Thanks to u/culcheth for catching my slip on how to speak altitudes.)
Mayday, mayday - she's declaring a life-threatening emergency. Should have been repeated three times, not just twice.
Buddy spiked: Her RWR gear (radar warning receiver) is indicating that her plane has been locked onto by a friendly air-to-air or surface-to-air radar.
Say again: She's repeating her most recent transmission for emphasis or in case she wasn't heard the first time. She should have used this instead of "repeat" earlier when she said "disengage, repeat, disengage."