ON MOTION FOR REHEARING
This case is now before us on a motion for rehearing filed by Airport Coach Service, Inc., appellant. In the motion, appellant through various contentions alleges that we were in error in several of the rulings contained in our original opinion. We have read and carefully considered the motion touching these rulings and for the sake of clarity deem the following explanations to be necessary.
Appellant argues that because we found that the trial court did have jurisdiction to interpret Certificate 2429-B we should have ourselves interpreted the certificate. We acknowledge our oversight in this respect. The same rules apply to the constfuction of order of an administrative agency as those applied to the construction of statutes. Trapp v. Shell Oil Co., 145 Tex. 323, 198 S.W.2d 424 (1946); State v. Bilbo, 378 S.W.2d 871 (Tex.Civ.App., Austin, 1964), modified 392 S.W.2d 121 (Tex.). Therefore the aim and object of construction is to ascertain the intent of the legislative body, or as here, the administering body. City of Fort Worth v. Westchester House, Inc., 274 S.W.2d 732 (Tex.Civ.App., Fort Worth, 1954, n. r. e.) The intention of the Railroad Commission, as expressed in the certificate, is a question of law and in arriving at a construction of the certificate, the court may consider the application made to and the order of the Railroad Commission. State v. Bilbo, supra.
Appellant’s Certificate of Convenience and Necessity No. 2429-B enumerates 12 specific routes over which appellant is authorized to operate. Included in the record is the original certificate dated December 7, 1970 and an amended certificate dated June 15, 1971, neither of which lists the Regional Airport as being included in the area of authorized service. The certificate does authorize service between Dallas and Greater Southwest International Airport located in Fort Worth and between Fort Worth and Love Field located in Dallas. This authority is given specifically by naming these points and by openly naming the highways to be used in traveling between these points. The certificate further lists Grapevine as a point of service but makes no mention of service to the D/FW Airport. It is an established rule of construction that the express mention or enumeration of one person or thing is equivalent to an express exclusion of all others. State v. Mauritz-Wells Co., 141 Tex. 634, 175 S.W.2d 238 (Tex.Sup.1943); City of Dallas v. Yarbrough, 399 S.W.2d 938 (Tex.Civ.App., Dallas, 1966, n. w. h.). We must therefore conclude that the Certificate as presented in the record does not authorize service to the Dallas/Fort Worth Regional Airport.
Appellant, however, would argue that the authority to serve the cities of Grapevine and Fort Worth would, by implication, include authority to serve the Regional Airport, parts of which fall within the boundaries of these two cities. The printed language in the certificate grants authority to appellant to serve all intermediate points on such twelve listed routes and by tacking, joining and combining such routes at common service points to render *575a coordinated or through service. It is clear, therefore, that service may be rendered only along those routes described between the various named cities and airports. If appellant could serve all portions of all cities or towns named in the certificate, no purpose would be served in naming specific routes or in allowing a city or municipality to have control over its streets and highways. Article 911a, V.A.T.S.; Yellow Cab Transit Co., Inc. v. Tuck et al., 115 S.W.2d 455 (Tex.Civ.App., Dallas, 1938, writ ref’d). Also, the Railroad Commission’s intention in naming those specific airports in Dallas and Fort Worth to be served would be clouded. We therefore must conclude that the intention of the Railroad Commission was not to give authority to appellant to serve the Regional Airport. No mention is ever made in the proceedings concerning the acquisition of Certificate 2429-B of the Regional Airport.2
Further, under Art. 46d, V.A.T.S., the Municipal Airport Act, a municipality is authorized to construct, operate, maintain, police and protect airports either within or without the territorial limits of the municipality. Further authority is given to enter into various service and supply contracts or leases for a term not to exceed 40 years and to adopt, amend and repeal ordinances, rules and regulations as the city shall deem necessary for the management, government and use of the airport. Art. 46d-6 & 46d-7.
In accordance with these powers, a Joint Operating Board was formed by the cities of Dallas and Forth Worth and certain ordinances were passed concerning the operation of the D/FW Airport. (See Footnote 1.) Because we have no reason to doubt the validity of these ordinances and because appellant has admitted that no application has been made to the Joint Board for permission to serve the Regional Airport, we conclude that appellant has no such authority.
It is our understanding that the appellant originally sought an interpretation of and an injunction against the enforcement of penal ordinances enacted by appellees in exercising their control over the airport and its operation. In support of a contention that the court should have enjoined the enforcement of various penal ordinances, appellant contends that the authority granted by Certificate 2429-B to serve the airport is a property right which will support an injunction and that any monopoly appellees might create for themselves is unlawful because it denies rights that the Legislature has granted to others. However, we have found that the Certificate 2429-B does not authorize appellant to serve the D/FW Regional Airport. We therefore conclude that the cities could give themselves a monopoly in the present situation, and that no previously granted rights had been denied. Therefore because not all of the elements required to enjoin a penal ordinance were present, the court lacked authority to do so.
In point six in his motion for rehearing, appellant contends that our holding that the nonjoinder of Irving and Grapevine does not support the affirmance of the summary judgment, the proper remedy being remand for joinder of these parties. However, assuming this point to be valid, our finding that those elements necessary to cause the injunction of a penal ordinance (see State v. Logue, supra) were lacking in this case still results in a finding of lack of jurisdiction. Therefore the presence of Irving and Grapevine would not have altered the final outcome of this case.
We must admit that the appellant’s complaint concerning the appropriateness of point of error number two does have merit. Point of error number two is in compli-*576anee with the decisions as rendered by the Supreme Court in Malooly Brothers, Inc. v. Napier, 461 S.W.2d 119 (Tex.Sup.1970) and we therefore find no basis for any criticism of this point.
Appellant finally argues that because we found that the trial court had no jurisdiction to determine the validity of the penal ordinances, this court erred in affirming the summary judgment on that part of the case. We did find that the trial court lacked jurisdiction to enjoin the enforcement of the penal ordinance and so stated in our opinion. However, the trial court did have jurisdiction to interpret the Certificate 2429-B which it failed to do and which we have now done. This interpretation is done as a matter of law and therefore we still remain convinced that the summary judgment based on this ground must be affirmed.
We have found no errors warranting the need for a rehearing of this cause. With the clarification of our original opinion appellant’s motion is therefore overruled.
. Appellant did at one time apply for an amendment to Certificate 242S-B to have D/FW Airport expressly included in its area o£ authority. However this application was subsequently withdrawn before any commission action was taken.