Mike Lisman
Co-Chief Operating Officer at TransDigm Group
Good morning, everyone. I'll start with our typical review of results by key market category. For the remainder of the call, I'll provide commentary on a pro forma basis compared to the prior year period in 2023, that is, assuming we own the same mix of businesses in both periods.
In the commercial market, which typically makes up close to 65% of our revenue, we will split our discussion into OEM and aftermarket. Our total commercial OEM revenue increased approximately 21% in Q2, compared with the prior year period. Sequentially, total commercial OEM revenues grew by about 12% compared to Q1.
Bookings in the quarter were strong compared to the same prior year period. These booking levels continue to support the commercial OEM guidance for revenue growth of around 20% for fiscal '24. OEM supply chain and labor challenges persist, but appear to be progressing. Broadly speaking, we continue to be encouraged by the elevated and healthy airline demand for new aircraft. Supply chains remain the primary bottleneck in this OEM production ramp-up.
As many of you know, concerns have recently arisen around the expected 737 MAX production rate ramp. Time will tell how this plays out. At this time, we remain cautious and are watching for a potential realignment of our current MAX order backlog to reflect the lower production rates.
The commercial OEM guidance we are giving today contains an appropriate, appropriate level of risk around the MAX production build rate for the balance of our '24 fiscal year. While both the 737 MAX risk, as well as other risks remain towards achieving the ramp-up across the broader aerospace sector, we're optimistic that our operating units are well positioned to support the higher production rates as they occur.
Now moving on to our commercial aftermarket business discussion. Total commercial aftermarket revenue increased by approximately 8% compared with the prior year period. I would like to provide a bit more color than is typical on our commercial aftermarket sub-markets, as the variation in growth rates seen this quarter across those sub-markets was much larger than usual. The 8% growth rate mentioned was primarily driven by the continued strength in our passenger sub-market, which is by far our largest sub-market.
Growth in our passenger sub-market was roughly 20% versus the prior year period, and this sub-market continues to perform exceptionally well. We also saw good growth in our interior sub-market of about this same rate when compared to prior year Q2. These increases were offset by declines in our freight and biz jet sub-markets. Freight was down roughly 15%, and biz jet was down in the 5% area. The freight decline was primarily a result of the continued return of belly capacity, consistent with what we discussed on our past few earnings calls. The biz jet decline as a result of tempering biz jet flight activity, which has continued to come down from the pandemic highs.
For the full year, and as you saw in today's guidance, our outlook for commercial aftermarket growth in the mid-teens is unchanged. We saw a number of elements in our Q2 results that make us confident. Namely Q2 bookings in commercial aftermarket were strong, running ahead of our expectations, significantly outpacing sales and supporting the full year growth outlook. Additionally, our Q2 point of sales data through our distribution partners, which can be a decent leading indicator was up significantly, well into the double-digits on a percentage basis.
Finally, a reminder; commercial aftermarket can be lumpy on a quarterly basis, both revenue and the bookings, not as lumpy as defense aftermarket, but lumpy nonetheless. Finally, note that our guide for mid-teens percentage growth across our total commercial aftermarket given today still incorporates a continued drag from the cargo and biz jet sub-markets for the balance of this fiscal year.
Now turning to broader market dynamics and referencing the most recent IATA traffic data for March. Global revenue passenger miles surpassed pre-pandemic levels for the first time in February 2024 and continued to do so in March. March '24 air traffic was about 1% above pre-pandemic, and IATA currently expects traffic to reach 104% of 2019 levels and 2024.
Domestic travel continues to surpass pre-pandemic levels. In the most recently reported traffic data for March, global domestic air traffic was up 6% compared to pre-pandemic. Domestic air travel growth has been driven significantly by outsized growth in China, which was up 14% in March compared to pre-pandemic. This is a significant improvement from China being down 3% a year ago in March of 2023.
Shifting over to the US domestic market, domestic air travel for March was about 4% above pre-pandemic traffic. International traffic has continued to make steady improvement over the past few months. It slightly surpassed pre-pandemic levels for the first time in February. In the most recently reported data for March, international travel was down just 2% compared to the pre-pandemic levels. And this marks a significant improvement from being down about 18% one year ago.
In summary, for the commercial aftermarket, we continue to see growth and our passenger and interior sub-markets indicative of the continuing positive trends and the post COVID passenger traffic recovery. Our biz jet and freight sub-markets are as we'd expect in light of the current trends in their underlying markets.
Now shifting to our defense market, which traditionally is at or below 35% of our total revenue. The defense market revenue, which includes both OEM and aftermarket revenues grew by approximately 21% compared with the prior year period. Q2 defense revenue growth was well distributed across our businesses and customer base. Additionally, we saw similar rates of growth in both the OEM and aftermarket components of our total defense market, with aftermarket running slightly ahead of the OEM.
We do not expect to see defense revenue growth rates as this 20% level, at this 20%-plus level continuing for the balance of the year, and we expect some moderation or tempering here, as you can tell from the guidance given today. Defense bookings were up significantly this quarter compared to the same prior year period and support the revised defense revenue growth guidance for the full year.
Additionally, this quarter, we saw growth in US government defense spend outlays, and we're hopeful, we'll continue to see steady growth here, but as we have said many times before, defense sales and bookings can be lumpy. We know the bookings and sales will come, but forecasting them with accuracy and precision, especially on a quarterly basis is difficult.
As Kevin mentioned earlier, we now expect our defense market revenue growth for this year to be in the mid-teens percentage range. This updated guidance for defense primarily reflects stronger than expected Q2 defense sales, as well as the good Q2 bookings.
Lastly, I'd like to wrap up by expressing how pleased I am by our operational performance in the second quarter of fiscal '24. Even though we saw some lumpiness in our most profitable end market commercial aftermarkets, our operating unit teams did an exceptional job of executing on our value drivers to generate strong results delivered this quarter. Our management teams remain committed to our consistent operating strategy and servicing the robust demand for our products as we continue through the balance of the year.
With that, I'd like to turn it over to our CFO, Sarah Wynne.
