If the first Planes film, a spin-off from Pixar's Cars, appeared to be propelled by merchandising opportunities rather than creative necessity, this action-packed sequel attempts to stand on its own landing gear with a stirring tale of heroism and self-sacrifice.

As the title suggests, Planes 2: Fire & Rescue immerses us in the daredevil world of fire-fighting, honouring the men and women - and aircraft - who "fly in when others are flying out".

It's a touching sentiment and screenwriter Jeffrey M Howard engineers some moving exchanges between the characters, some of whom are a splutter away from the scrap heap.

Director Bobs Gannaway employs the 3D format to striking effect in aerial sequences and the animation of raging infernos is impressively realistic.

However, there's an inescapable feeling that this gung-ho adventure should have taken a flight path directly to the home formats rather than the big screen.

Soaring over Propwash Junction with his mentor Skipper (voiced by Stacy Keach), Dusty Crophopper (Dane Cook) suffers a malfunction.

Back at the hanger, trusted mechanic Dottie (Teri Hatcher) diagnoses a failing gearbox.

"From now on, you have to keep down your torque to less than 80 percent," she instructs Dusty, putting an end to his illustrious racing career.

Dusty angrily defies Dottie and careens into the town's airport, causing a small fire.

The incident casts doubt on the ability of veteran fire and rescue truck Mayday (Hal Holbrook) to service the airport's needs.

So Dusty agrees to abandon his racing dreams in order to earn his certificate as the town's fire-fighting plane.

The plucky crop duster heads to Piston Peak National Park to train under helicopter Blade Ranger (Ed Harris), who was once a TV star, and his team including scooper Lil' Dipper (Julie Bowen), helicopter Windlifter (Wes Studi) and ex-military transport plane Cabbie (Dale Dye).

As Dusty masters the art of airborne fire-fighting, he also learns valuable lessons about friendship and endurance.

As Blade reminds him, "If you give up today, think of all the lives you can't save tomorrow."

Planes 2: Fire & Rescue is geared towards younger viewers, hammering home the importance of team work and the valuable contribution of emergency services.

There are a handful of verbal and visual gags to engage older audiences: a front cover of industry magazine Cariety; a bar patron drunkenly confiding, "She left me for a hybrid. I didn't hear it coming!"

A spoof of the long-running motorcycle police series CHiPs includes a cameo for Erik Estrada as Blade Ranger's partner on air patrol.

On the whole, though, Gannaway's sequel lacks the sophistication and emotional richness of yesteryear's Frozen or recent Pixar fare.

Animation is crisp and colourful and the vocal performances are similarly warm so audiences feel a toasty glow before the first plumes of smoke from the computer-generated blazes.