diff --git a/simgear/package/CatalogTest.cxx b/simgear/package/CatalogTest.cxx
index 426bfd88..fd90ab86 100644
--- a/simgear/package/CatalogTest.cxx
+++ b/simgear/package/CatalogTest.cxx
@@ -173,6 +173,8 @@ int parseTest()
     SG_CHECK_EQUAL(thumb.path, "exterior.png");
 
 // test variants
+    SG_CHECK_EQUAL(p2->parentIdForVariant(0), std::string());
+
     try {
         p2->indexOfVariant("fofofo");
         SG_TEST_FAIL("lookup of non-existant variant did not throw");
@@ -186,6 +188,8 @@ int parseTest()
     unsigned int skisVariant = p2->indexOfVariant("c172p-skis");
     SG_VERIFY(skisVariant > 0);
 
+    SG_CHECK_EQUAL(p2->parentIdForVariant(skisVariantFull), "c172p");
+
     SG_CHECK_EQUAL(skisVariant, skisVariantFull);
 
     SG_CHECK_EQUAL(p2->getLocalisedProp("description", skisVariant),
@@ -195,6 +199,7 @@ int parseTest()
 
     unsigned int floatsVariant = p2->indexOfVariant("c172p-floats");
     SG_VERIFY(floatsVariant > 0);
+    SG_CHECK_EQUAL(p2->parentIdForVariant(floatsVariant), "c172p");
 
     SG_CHECK_EQUAL(p2->getLocalisedProp("description", floatsVariant),
                    "A plane with floats");
@@ -215,6 +220,19 @@ int parseTest()
     SG_CHECK_EQUAL(thumb2.url, "http://foo.bar.com/thumb-floats.png");
     SG_CHECK_EQUAL(thumb2.path, "thumb-floats.png");
 
+// test multiple primary
+    unsigned int rVariant = p2->indexOfVariant("c172r");
+    SG_VERIFY(rVariant > 0);
+
+    SG_CHECK_EQUAL(p2->parentIdForVariant(rVariant), std::string());
+
+    unsigned int rFloatVariant = p2->indexOfVariant("c172r-floats");
+    SG_VERIFY(rFloatVariant > 0);
+    SG_CHECK_EQUAL(p2->parentIdForVariant(rFloatVariant), std::string("c172r"));
+
+    string_list primaries = {"c172p", "c172r"};
+    SG_VERIFY(p2->primaryVariants() == primaries);
+
 // test filtering / searching too
     string_set tags(p2->tags());
     SG_CHECK_EQUAL(tags.size(), 4);
diff --git a/simgear/package/Package.cxx b/simgear/package/Package.cxx
index b5361eb9..17772f94 100644
--- a/simgear/package/Package.cxx
+++ b/simgear/package/Package.cxx
@@ -291,7 +291,7 @@ string_list Package::downloadUrls() const
         return r;
     }
 
-    BOOST_FOREACH(SGPropertyNode* dl, m_props->getChildren("url")) {
+    for (auto dl : m_props->getChildren("url")) {
         r.push_back(dl->getStringValue());
     }
     return r;
@@ -412,7 +412,38 @@ SGPropertyNode_ptr Package::propsForVariant(const unsigned int vIndex, const cha
         return m_props;
     }
 
-    throw sg_exception("Unknow variant in package " + id());
+    throw sg_exception("Unknown variant in package " + id());
+}
+
+std::string Package::parentIdForVariant(unsigned int variantIndex) const
+{
+    const std::string parentId = propsForVariant(variantIndex)->getStringValue("variant-of");
+    if ((variantIndex == 0) || (parentId == "_package_")) {
+        return std::string();
+    }
+
+    if (parentId.empty()) {
+        // this is a variant without a variant-of, so assume its parent is
+        // the first primary
+        return m_variants.front();
+    }
+
+    assert(indexOfVariant(parentId) >= 0);
+    return parentId;
+}
+
+string_list Package::primaryVariants() const
+{
+    string_list result;
+    for (unsigned int v = 0; v < m_variants.size(); ++v) {
+        const auto pr = parentIdForVariant(v);
+        if (pr.empty()) {
+            result.push_back(m_variants.at(v));
+        }
+    }
+    assert(!result.empty());
+    assert(result.front() == id());
+    return result;
 }
 
 Package::Thumbnail Package::thumbnailForVariant(unsigned int vIndex) const
diff --git a/simgear/package/Package.hxx b/simgear/package/Package.hxx
index 54dd4667..bbb9582c 100644
--- a/simgear/package/Package.hxx
+++ b/simgear/package/Package.hxx
@@ -62,15 +62,25 @@ public:
     existingInstall(const InstallCallback& cb = InstallCallback()) const;
 
     bool isInstalled() const;
-    
+
+    /**
+     * package ID
+     */
     std::string id() const;
 
     /**
-     * Variant IDs. Note the primary ID will always be included as 
-     * variants()[0], to simplify enumerating all variants
+     * Variant IDs
      */
     string_list variants() const;
 
+    /**
+     * All variants without a parent, i.e top-level variants in this package.
+     * Often this is a single-element list matching id() above, but when
+     * packages contain multiple primary aircraft, this will have multiple
+     * elements.
+     */
+    string_list primaryVariants() const;
+
     /**
      * Fully-qualified ID, including our catalog'd ID
      */
@@ -89,6 +99,8 @@ public:
     /**
      * human-readable name - note this is probably not localised,
      * although this is not ruled out for the future.
+     * 
+     * Deprecated - please use nameForVariant
      */
     std::string name() const;
 
@@ -101,6 +113,9 @@ public:
 
     /**
      * syntactic sugar to get the localised description
+     *
+     * Deprecated - please use getLocalisedProp to get the variant-specific
+     * description.
      */
     std::string description() const;
     
@@ -182,6 +197,15 @@ public:
      * same as the primary ID, depending on the aircraft author
      */
     std::string dirName() const;
+
+    /**
+     * Return the parent variant of a variant. This will be the emtpy string if
+     * the variant is primary (top-level), otherwise the local (non-qualified)
+     * ID. This allows establishing a heirarchy of variants within the package.
+     * Note at present most code assumes a maxiumum two-level deep heirarchy
+     * (parents and children)
+     */
+    std::string parentIdForVariant(unsigned int variantIndex) const;
 private:
     SGPath pathOnDisk() const;
 
diff --git a/simgear/package/catalogTest1/catalog.xml b/simgear/package/catalogTest1/catalog.xml
index b226ca3d..26fb7025 100644
--- a/simgear/package/catalogTest1/catalog.xml
+++ b/simgear/package/catalogTest1/catalog.xml
@@ -99,6 +99,8 @@
             <name>C172 with skis</name>
             <description>A plane with skis</description>
 
+            <variant-of>c172p</variant-of>
+
             <preview>
               <type>exterior</type>
               <path>thumb-exterior-skis.png</path>
@@ -112,6 +114,30 @@
             </preview>
         </variant>
 
+        <variant>
+            <id>c172r</id>
+            <name>C172R</name>
+            <description>Equally good version of the C172</description>
+            <variant-of>_package_</variant-of>
+            <preview>
+              <type>panel</type>
+              <path>thumb-panel.png</path>
+              <url>http://foo.bar.com/thumb-panel.png</url>
+            </preview>
+        </variant>
+
+        <variant>
+            <id>c172r-floats</id>
+            <name>C172R-floats</name>
+            <description>Equally good version of the C172 with floats</description>
+            <variant-of>c172r</variant-of>
+            <preview>
+              <type>panel</type>
+              <path>thumb-panel.png</path>
+              <url>http://foo.bar.com/thumb-panel.png</url>
+            </preview>
+        </variant>
+
         <md5>ec0e2ffdf98d6a5c05c77445e5447ff5</md5>
         <url>http://localhost:2000/catalogTest1/c172p.zip</url>