United Technologies Corporation was incorporated in Delaware in 1934. UTC provides high technology products and services to the building systems and aerospace industries worldwide. Growth is attributable primarily to the internal development of our existing businesses and to acquisitions. The following description of our business should be read in conjunction with "Management’s Discussion and Analysis of Financial Condition and Results of Operations" in our 2018 Annual Report including the information contained therein under the heading "Business Overview."
We may not complete the combination with Raytheon or complete the combination within the time frame we anticipate; the combined business may underperform relative to our expectations; the combination may cause our financial results to differ from our expectations or the expectations of the investment community; we may not be able to achieve anticipated cost savings or other anticipated benefits.
We are a global provider of high technology products and services to the building systems and aerospace industries. Our operations for the periods presented herein are classified into four principal business segments: Otis, Carrier, Pratt & Whitney, and Collins Aerospace Systems. Otis and Carrier are referred to as the "commercial businesses," while Pratt & Whitney and Collins Aerospace Systems are referred to as the "aerospace businesses."
The current status of significant factors affecting our business environment in 2019 is discussed below. For additional discussion, refer to the "Business Overview" section in Management's Discussion and Analysis of Financial Condition and Results of Operations in our 2018 Annual Report, which is incorporated by reference in our 2018 Form 10-K.
Our worldwide operations can be affected by industrial, economic and political factors on both a regional and global level. Our operations include original equipment manufacturing (OEM) and extensive related aftermarket parts and services in both our commercial and aerospace businesses. Our business mix also reflects the combination of shorter cycles at Carrier and in our commercial aerospace spares businesses, and longer cycles at Otis and in our aerospace OEM and aftermarket maintenance businesses. Our customers are in the public and private sectors, and our businesses reflect an extensive geographic diversification that has evolved with continued globalization.