While cruising the NYSE's top gainers this week, I spotted not one, but two, chopper stocks. No, not like the customized Harley-Davidson (NYSE:HOG) Dennis Hopper rode in Easy Rider -- the other kind of chopper. So why are these companies lifting off today? Let's take a quick look at each.

First up is Bristow Group (NYSE:BRS), which primarily provides helicopter transport services to the offshore oil and gas industry. That is, they move people and equipment between onshore bases and offshore rigs and platforms. It would appear to be a decent pick-and-shovel play, to borrow an overused gold rush analogy. Nevertheless, over the past two years, Bristow has badly lagged the oil service sector, known to some in ETF form as Oil Services HOLDRs (AMEX:OIH). Were there an offshore-only oil service index, I imagine Bristow would show even more poorly in the comparison.

The company finds itself in disfavor thanks to fraudulent practices in its past. However, management has been overhauled, and there's reason to believe that the company has begun to regain investors' trust. Tuesday's earnings results should help that reconciliation along. Annual gross revenues from helicopter services rose nearly 17% on 3% more flight hours, reflecting a strong pricing environment. Record quarterly revenues and operating profit seem to have caught quite a lot of folks flatfooted today. The company sees strong demand ahead and is embarking on a significant fleet expansion. Fortunately, its balance sheet looks strong enough to support this move.

The coattail rider is rival CHC Helicopter (NYSE:FLI). CHC's concurrent share price rise appears to be a case of somewhat lazy thinking: "Hey, these here helicopter companies are making some real dough." But CHC doesn't have the balance sheet strength or earnings growth of Bristow. CHC is trading at a premium to Bristow, which would be totally baffling if it weren't for Bristow's past misdeeds.

There are a lot of ways to invest in the strong fundamentals of the offshore industry. I'm not sure helicopters is the best way to do it when there are strong, better diversified, global operators out there like Schlumberger (NYSE:SLB) and Baker Hughes (NYSE:BHI). If helicopters really spin your rotor blades, however, Bristow Group appears to be the best option in the space.

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Fool contributor Toby Shute doesn't own shares in any company mentioned. The Motley Fool has a disclosure policy.